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Master Lock Heavy-Duty Coupler and Latch Lock Combo for 1-7/8", 2", 2-5/16" Couplers

Master Lock Heavy-Duty Coupler and Latch Lock Combo for 1-7/8", 2", 2-5/16" Couplers

Item # 3784DAT

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Trailer Coupler Locks

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Master Lock Heavy-Duty Coupler and Latch Lock Combo for 1-7/8", 2", 2-5/16" Couplers Steel 3784DAT
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Product Images

Master Lock Heavy-Duty Coupler and Latch Lock Combo for 1-7/8", 2", 2-5/16" Couplers Steel 3784DAT
3784DAT - Steel Master Lock Trailer Coupler Locks

In Use/Installed

Trailer Coupler Locks 3784DAT - Keyed Unique - Master Lock
3784DAT - Fits 2-5/16 Inch Ball Master Lock Surround Lock
Master Lock Fits 2-5/16 Inch Ball Trailer Coupler Locks - 3784DAT
Master Lock Fits 2-5/16 Inch Ball Trailer Coupler Locks - 3784DAT
Master Lock Trailer Coupler Locks - 3784DAT

  • Surround Lock
  • Fits 2-5/16 Inch Ball
  • Master Lock
  • Keyed Unique
  • Universal Application Lock
  • Steel
Whether your trailer is being towed or being stowed, this rugged lock combo deters trailer theft. Heavy-duty steel coupler lock fully surrounds coupler when trailer is unhitched. Keyed-alike latch lock secures coupler to tow vehicle during transit. Lowest Prices for the best trailer coupler locks from Master Lock. Master Lock Heavy-Duty Coupler and Latch Lock Combo for 1-7/8", 2", 2-5/16" Couplers part number 3784DAT can be ordered online at etrailer.com or call 800-298-8924 for expert service.


  • All Info
  • Reviews (57)
  • Q & A (26)
  • Videos (1)
  • Photos
  • Why etrailer?

Master Lock Trailer Coupler Locks - 3784DAT

Whether your trailer is being towed or being stowed, this rugged lock combo deters trailer theft. Heavy-duty steel coupler lock fully surrounds coupler when trailer is unhitched. Keyed-alike latch lock secures coupler to tow vehicle during transit.


Features:

  • Coupler lock combo deters theft of your trailer while it's parked or being towed
  • Riveted, laminated steel shell fully encloses your ball coupler to prevent towaway trailer theft
    • Advanced locking mechanism makes lock difficult to pick or pry open
    • Rugged, rust-resistant construction withstands impact and weather
  • Latch lock secures your trigger-style coupler latch to prevent theft of trailer while it's hitched up
  • Keyway covers on both locks keep out dirt and moisture
  • Conveniently keyed alike - 2 keys included


Specs:

  • Application: most 1-7/8", 2", and 2-5/16" ball couplers
    • Works with Reese, Fulton, Valley, Atwood, Shelby, Putnam, Bulldog, Dutton-Lainson, and UFP couplers
  • Limited lifetime warranty


When it comes time to protect your trailer that has a 1-7/8", 2", or 2-5/16" ball coupler, this heavy-duty Master Lock trailer coupler lock set will provide both security and peace of mind. The rust-resistant, laminated steel shell of the coupler lock fully surrounds your coupler, preventing access to the ball hole when your trailer is unhitched. The conveniently keyed-alike latch lock keeps your trigger-latch-style coupler secured to your tow vehicle when you're in transit. And the key hole covers on both locks keep out dust and moisture. So whether you are towing or stowing your trailer, you will enjoy peace of mind that the trailer is secure.


Coupler Lock Installation

To ensure a snug fit, UFP and some 1-7/8" couplers will require you to insert the included adapter into the top of the lock.


  1. Insert the ball-like bracket up into the coupler's hitch ball recess.
  2. Turn the key 90 degrees to unlock the lock.
  3. Push the lock toward the coupler as far as it will go. The lock will ratchet until it's tight.
  4. Turn the key 90 degrees to lock the unit.


3784DAT MasterLock Universal-Fit Heavy-Duty Trailer Coupler Lock




Video of Master Lock Heavy-Duty Coupler and Latch Lock Combo for 1-7/8", 2", 2-5/16" Couplers


Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Master Lock Universal Heavy-Duty Trailer Coupler and Latch Lock Review

Today well be reviewing the Master Lock Universal Heavy Duty Trailer Coupler and Latch Lock, part number 3784dat. This Master Lock prevents theft from the trailer by encasing the coupler in steel and preventing hook up designed for use when trailers not in tow. Constructed with a laminated, riveted steel frame, and additional steel on top and sides of ball enhances security. This Master Lock fits most 2 5/16 ball couplers including the straight lip, road lip, and surge brake hydraulic couplers. The Master Lock has an integrated weather resistant cover that keeps dirt and moisture out of the key way, includes two keys and has a limited lifetime warranty. Now that weve gone over some of the features of the Master Lock, well show you how to install it.

To begin our installation we will first uncover the key hole with the protective covering and insert the key to release a coupler lock. We will then set the trailer coupler onto the lock sliding the ball into the inner part of the lock, and then using the key to secure it in place. Once the trailer coupler is secured to the Master Lock, we will then move to the top of the trailer coupler and insert the trailer coupler latch lock and secure it with the key lock. And, thats it for todays review of the Master Lock Universal Heavy Duty Trailer Coupler and Latch Lock, part number 3784dat.


Customer Reviews

Master Lock Heavy-Duty Coupler and Latch Lock Combo for 1-7/8", 2", 2-5/16" Couplers - 3784DAT

Average Customer Rating:  4.4 out of 5 stars   (57 Customer Reviews)

Whether your trailer is being towed or being stowed, this rugged lock combo deters trailer theft. Heavy-duty steel coupler lock fully surrounds coupler when trailer is unhitched. Keyed-alike latch lock secures coupler to tow vehicle during transit.

- 3784DAT

by:


Strongly recommend. Very sturdy. No lock is unbeatable, but this one would take enough time and effort that most thieves would give up and move on to an easier target. I truly doubt you could break this lock off with a crow bar or sledge in less than 15 minutes. The only con was the directions for use. They weren't very clear, but 60 seconds of trial and error answered all the questions I had. It's a pretty simple device. 574478



- 3784DAT

by:


The products were excellent and worked out well. I did have a slight problem with the plastic packaging being opened, when I received it. It could have happened during shipping though. I just wanted you to know. 569059



- 3784DAT

by:


Very pleased with the response from etrailer on the coupler lock set. Easy ordering, quick shipping time and the exact product that was ordered! i would definitely recommend etrailer as a great source for accessorizing your trailer! Wish I would have found them sooner! 560271



- 3784DAT

by:


I have purchased these products from you before. These locks work great. 127004



- 3784DAT

by:


Its awesome that its keyed the same and fits all sizes of receivers. I reccomend this product. 565593



- 3784DAT

by:


Great lock thats easy to use and secures your trailer so some a**hole can't back up, hitch up and take off with your trailer. 551975



- 3784DAT

by:


After the theft of our wood trailer, we purchased three master lock heavy duty coupler and latch lock combo for each of our three trailers - wood, boat, and camp trailer. The lock system has several security components allowing less possibility of break in and theft of the trailer. The wood trailer lock fits well and has allowed us the freedom to park the trailer outside of our gated property without the fear of theft. We will use the other two when in use of the boat/boat trailer at the parking lot to secure the trailer from theft as well as the camp trailer while camped from place to place to allow us the freedom to travel away from the trailer during our stay in those locations without the concern of theft. Well worth the price in giving us a peace of mind. I only wish we could have had them keyed to match so we did not have to keep three sets of keys on our key rings and remember which goes to which. 124309



- 3784DAT

by:


I have not installed it yet but it looks stronger than the aluminum one I have on there now. 448976



- 3784DAT

by:


Price was good, shipping was fast. The coupler lock works for me and I am satisfied with my purchase. However, the lock does not fit snuggly on the coupler. I feel that it is secure and provides me peace of mind as there have been a rash of trailer/equipment thefts in my area recently. I suspect the reason it isn't snug is because it is designed to fit several different coupler sizes. Nevertheless, I don't think anyone will be able to remove the lock easily so I feel confident that my trailer is secure. 97981



- 3784DAT

by:


Rated as good just because it seems better than most I could find but.... Looks good but looks can be deceiving; fits loose, black bottom part is plastic and probably couldn't fend off a regular hammer let alone a 5 pound or more which would expose the guts of the lock...game over. Grey housing looks like steel but have my doubts about its quality/strength. I would like to see a video of how long it would last against a crow bar and 5 pound hammer... my guess, not long. May return it. 244074


Comments

Yet another good reason I do business with etrailer, you actually follow up. You do know that most companies talk about doing that but never do, right? No one has tried to break into the trailer lock so all I can say is that its doing the job as a deterrent.

J - 02/11/2018

34585

- 3784DAT

by:


Purchased for a 2" receiver and although it is a substantial, heavy duty unit it fits "sloppily" on the hitch and you need to use a 2" x 2" metal shim that is supplied with the lock that slides under the top of the unit. Over time, that shim could become misplaced. I am going to try and use some industrial double sided tape to hold it in place so it won't get set aside and lost when not in use. It does fully cover the hitch (sides, top and bottom) and looks like it will deter thief's. 133570



- 3784DAT

by:


Works and looks great, Did have to play around with it a little before figuring out the best way to install that would make a tight fit. Did use the additional part, that is included for 1 7/8 hitch, on my 2 5/16 A -frame hitch to make a snug fit. When installed, the looks are very deterring in the sense that it looks like a lot of work to cut off, not to mention covers the entire ball hitch. Nice work MasterLock. 111624


Comments

Have been very happy with this lock and have had a lot of people ask where I bought it. Still looks and works great and has worked well even in below zero weather since we moved to the north where it gets much colder over the winter months. I still recommend this to anyone looking for that total secure hitch look and feel.

Kenneth S - 12/31/2014

8309

- 3784DAT

by:


E trailer says I bought this a year ago. Actually we bought 2. 1 for a jobsite trailer and 1 for an equipment trailer. About 6 months ago our job trailer had a robbery attempt. They never touched the ball lock, but can opened the door. If it was just a pad lock I am sure they would have taken the trailer. One of our equipment trailers was taken, a couple of years ago, and that only had a pad lock, and was parked on our property. It takes a little time to get used to installing it, but after a couple of times it get very easy. 304472



- 3784DAT

by:


I live in a small town in western Texas, and this year we've had some crazy weather, from deep freezes, heavy rains winds and hail, to extreme heat. This lock has handled every minute of it. I've had this lock for a year now and it works just as great as it did the 1st day I got it. Highly recommend. 275223



- 3784DAT

by:


There was an adapter to make it fit my hitch, had to beat it on with a hammer to get it together, it had to bend the adapter to fit... The pin lock is pretty much a joke, you'd just have to bend it and it would slide right out.... But it does lock on the hitch and you would have a hard time getting it off, so it will do what I bought it for... They could have done more refining to the design before making it a fits them all... As far as etrailer, they did just fine.... very fast shipping 496718



- 3784DAT

by:


Well made, easy to use. 22593


Comments

Will the latch lock fit a Titan surge coupler Aero 7500. The security pin on the coupler is awfully small.

-- comment by: Don - 07/22/2013

1794

I pulled one of the MasterLock coupler locks and one of the Titan Aero couplers from our warehouse and did some measuring. The MasterLock pin has an OD of .275 inches. The retention pin on the coupler measures .311 inches. The pin diameter checks out, the problem is the length. The pin would not be long enough to span through the latch and allow the lock to engage.

-- Patrick B - 7/30/2013


- 3784DAT

by:


I bought this lock because could not get the Blaylock EZ Lock Trailer Coupler Lock for 1-7/8", 2", and 2-5/16" Couplers for another month. ( Out of stock) The Master Lock is OK but as a lot of the reviews on the lock it is so loose seems like going to fall off when mounted on the trailer. I have the 2-5/16 coupler. They have a good idea but did not carry out on there idea to make it a good product. So not to very happy with it. I will have to do some mods on it to make it fit better. Not dissatisfied with etrailer have bought a lot of items from them and had no trouble with the order or the shipping and they keep you informed THANKS etrailer 192040



- 3784DAT

by:


Coupler lock needs much improvement to make it a more secure product. nothing is tamper proof but this item lacks secure quality. I am making the necessary modifications to make it better. Rivets are a poor choice for assembly but cheaper than welding. rivets can be cut off with one blow of a chisel. 490439


Comments

The sad fact is that if a thief is determined to steal your property, they are going to do it. Using locking products will add a level of deterrence, the hope is that the thief will move on to an easier target, leaving your property alone. For the most part, locks are for keeping honest people honest.

-- Mike L - 03/29/2018

36592

- 3784DAT

by:


Shopping with etrailer is great! Coupler lock does fit, but it seems a little loose. The latch lock fits tight and seems fine. The only way to get a "great" review is if someone attempts to steal the trailer and cannot, which I hope doesn't happen. 284358



- 3784DAT

by:


This lock is awesome! I have the older model of this, and it didn't fit my boat trailer very good.... BUT this model fits snug and it looks extremely tough and deterring. This lock is a huge improvement over the old model. I would definitely buy another, and I am very happy with my purchase. I use this lock to keep my 28' Offshore fishing boat secure, and I can sleep at night 280260



- 3784DAT

by:


Fantastic service. Product was just as advertised and was promptly delivered. this is my second purchase from this company and it is now my go to source for my trailer needs. 556193



- 3784DAT

by:


We purchased 2 of these one for the trailer and one for our boat after we had had a theft of a wood splitter stolen that had a heavy duty security lock from another company. These locks are terrific! Would recommend to anyone who can use this type of lock. No we never recovered the wood splitter 542848



- 3784DAT

by:


I received my purchased in a few days and I’ve been pleased with etrailer. I would definitely purchase again from them. 518055



- 3784DAT

by:


Fast shipping. The coupler lock fits my coupler as it should. 409767


Comments

This lock has continued to be dependable after one year if being exposed to the weather.

Rex - 07/23/2018

41322

- 3784DAT

by:


I have a very heavy duty pull hitch and lock doesn't fix as snug as I would like but still secures trailer. 587906



- 3784DAT

by:


It works great, I purchased 2 of these locks for my trailers. They are used ever day to keep my trailers protected from thieves. 583392



- 3784DAT

by:


Works great - fits well - looks like it will definitely do the job. 483101



- 3784DAT

by:


Great theft deterrent little tricky getting in place but works good. 456016



- 3784DAT

by:


Works like it should. Very easy to put on took only a few minutes and was ready to go. 446216



- 3784DAT

by:


It’s not coming off without serious power tools and a lot of noise. 440178



- 3784DAT

by:


Reesa T was very helpful in referring me to this product. She answered all of my questions and made the experience enjoyable. Thank you! 433595



- 3784DAT

by:


Great product. I do wish I could order additional keys. Most secure box tongue lock I’ve seen. 430428



- 3784DAT

by:


I haven't used the item yet so I can't give an honest review 413909



- 3784DAT

by:


love it quick delivery 377996



- 3784DAT

by:


The product fits well. Not a big fan of the vacuum packaging. They are alway hard to open and can cut you if you're not real careful. I know it looks great on the shelf at the store but it is a real pain in the butt to open. I'm wondering how tough this thing is seeing it in person now. I hope someone doesn't just stick a crowbar in it and pry it off. 377150



- 3784DAT

by:


Great product and great service shipping was fast 373581



- 3784DAT

by:


Excellent product, it was everything the review said it would be. Easy to use, but yet strong and study when in place. Would recommend to everyone. 365865



- 3784DAT

by:


This lock is plastic on the bottom and metal on the top. I think having the two locks for the connection is better than one. There is no opening for a crow bar. 338133



- 3784DAT

by:


poor lasted about a month and lock system would not function. 331954



- 3784DAT

by:


Great products, great service, fast del ivery 310362



- 3784DAT

by:


Outstanding customer service!!! Product quality was much better than I expected! 303049



- 3784DAT

by:


Receiver lock was delivered quickly and fits my 2 5/8 hitch perfectly. 284943



- 3784DAT

by:


works 284107



- 3784DAT

by:


I recommend this lock combo for the trailer coupler.I like the key alike option. 259752



- 3784DAT

by:


Great Product 204634



- 3784DAT

by:


When I got the lock it was even better than I could have even thought. Great product great price you will not be disapointed! 172598



- 3784DAT

by:


from Wentzville, USA to Quebec City, Canada in 3 days..WOW thank's Etrailer !!! 147968



- 3784DAT

by:


Very solid. Should do a great job of making it difficult for thieves. 117606



- 3784DAT

by:


Quality, cost effective solution. My company has started to use these to secure trailer units that we store at remote, semi-secure locations where they are used. We have also bought some to lock-out trailer units that are in need of service. Being able to order them with matching keys would be a benefit. 116759



- 3784DAT

by:


Great product and easy to install. 116527


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Show More Reviews

Ask the Experts about this Master Lock Trailer Coupler Locks
Do you have a question about this Trailer Coupler Lock?


  • How Theft-Proof is the Deadbolt Trailer Coupler Lock # 28012
  • Locks are for keeping honest folks honest, just about any lock can eventually be defeated if the crook is determined enough. The lock you mention, part # 28012 would provide what I would call minimal deterrence against theft. If there are two identical boat trailers parked side by side, one using the # 28012 lock, and the other unlocked, the 20812 will do its job and deter the crook from taking your trailer. One quick snip with some bolt cutters, and the lock will be defeated, but the...
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  • Recommended Trailer Coupler Lock for a 2-5/16
  • I want to start off by saying that any trailer lock that you purchase will never be able to fully secure your trailer from a thief. If they are determined enough to bring equipment with them to remove a lock then given enough time they will be able to remove a lock. This will be the case no matter what you what you are looking to put a lock on. With that being said, the Blaylock EZ Lock Trailer Coupler Lock # BLTL-33 that you referenced is a great lock that has received many great reviews...
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  • Recommended Locks for 2-5/16-Inch Squeeze-Latch Type Trailer Coupler
  • To secure your squeeze-latch type coupler such as # CTA-280 you can use a latch pin lock such as # 2847DAT, a coupler lock such as # FA86-0015-312 or choose a combination kit with both, such as the Master Lock # 3784DAT. Using this Master Lock kit will give your trailer dual protection from theft by securing both the latch mechanism and the coupler head.
    view full answer...

  • Best Coupler Lock Options for a 2015 Ranger Trail Boat Trailer
  • We have a few different universal options that I recommend choosing from. The Master Lock Trailer Coupler Lock # ML389DAT is a great option because it has a bright red color to draw attention to the fact that there is a lock on the trailer. Since the idea behind a lock is to deter theft, drawing attention to the lock will help to intimidate a would-be trailer thief. One of the most popular options is the Fastway Trailer Coupler Lock # DT25013KA. You can order this lock keyed alike...
    view full answer...

  • Recommended Coupler Locks for Bulldog Cast Head Coupler # BDA256C0317
  • I pulled one of the Bulldog # BDA256C0317 couplers off the shelf, and tested it with various coupler locks. Other than the deadbolt style locks like the # RC6SS that pass through the latch, I found three locks that would work pretty well for you. The fit of the Blaylock EZ Lock # BLTL-33 was a bit loose, but once the locking bar was slid into place, I was unable to remove the lock by hand, although a pry bar might get it off. The Master Lock Universal Trailer Coupler Lock, # 379DAT...
    view full answer...

  • Recommendation for Coupler and Hitch Locks Keyed the Same
  • I have a solution for you but if you were to order more than 1 of lock set # 3784DAT the locks in each individual set would be keyed the same but the locks would differ from set to set. What I recommend is to use a coupler lock such as # DT25013KA (which looks like what you have in the picture). Select the keyed alike option and then how many you need in the quantity box and you will receive all of them keyed the same. So that is one key. Then for a standard 2 inch hitch lock I recommend...
    view full answer...

  • Recommendation for Class V Hitch Lock and Coupler Lock
  • There are many hitch receiver sizes available in Class V. For a 2 inch receiver, I recommend the Bulldog Lifelong Trigger-Style Coupler Lock and 2" Trailer Hitch Receiver Lock - Chrome # BD580404 to give you both the hitch lock and the trigger coupler lock. For a 2-1/2 inch receiver, I recommend the Trailer Hitch Receiver Lock - Extra Long - Flush Design for 2-1/2" Trailer Hitches # RH5-XL. For a 3 inch receiver, I recommend the hitch lock # WS05. This hitch lock is one of the...
    view full answer...

  • Recommendation for a Trailer Coupler Lock that Will Fit a 4 Inch Wide Trailer Coupler
  • I spoke with my contact at Master Lock about the Trailer Coupler Lock # 3784DAT. They were not certain if the lock is compatible with a 4 inch wide coupler. But, we do have other options. I have compiled a list below of the trailer coupler locks that will fit a 4 inch wide coupler. Fastway Universal Trailer Coupler Lock, # DT25013KA Trailer Coupler Lock, Gorilla Guard, # 63227 (for 2-5/16 inch couplers)
    view full answer...

  • Will the Master Lock Heavy-Duty Coupler and Latch Lock # 3784DAT fit a Bulldog Coupler
  • Yes, we have found that the Master Lock Heavy-Duty Coupler and Latch Lock Combo # 3784DAT that you referenced will work on Bulldog couplers so it should work very well for yours. I attached a review video for you to check out also.
    view full answer...

  • Does Master Lock Heavy-Duty Coupler and Latch Lock Combo # 3784DAT Fit a 2 Inch Coupler
  • That's interesting, because Master Lock coupler lock # 3784DAT does indeed fit a 1-7/8 inch. 2 inch, and 2-5/16 inch coupler. Even the instructions from their site show it fitting a 1-7/8 and 2-5/16 inch coupler. They don't show the 2 inch because it does not require any special steps (there is a little insert, included, that has to be on for 1-7/8 inch and UFP couplers but removed otherwise). But this may not be the best option for coupler # BD43805W0317. It doesn't have a flange...
    view full answer...

  • Recommendation for a Coupler Lock for a Collar-Loc Trailer Coupler
  • Master Lock coupler lock # 3784DAT is not the best option for a Collar-Lok coupler. For a Collar-Lok coupler I recommend a lock designed for then such as # BLTL-23 (2-5/16 inch ball), # BLTL-20-40D (1-7/8 to 2-5/16 inch balls), or # BLTL-22 (2 inch ball).
    view full answer...

  • What Material is the Trailer Coupler Latch Lock # 2878DAT Made From
  • The 7/8" Wide Trailer Coupler Latch Lock # 2878DAT is made of hardened steel. As far as how easy it is to defeat, ultimately any lock can be defeated given enough time and the right tools. Since there is no gauge of how "breakeable" a specific lock is, we recommend making your setup look intimidating to deter would-be thieves. If you are wanting to deter theft of your trailer when it is coupled then the Bulldog # BD580404 is a great option because it has a coupler lock and a ball...
    view full answer...

  • Recommended Trailer Coupler Lock for A-Frame with Trigger Latch
  • Do you have a photo of your trailer coupler? If it looks like the A-Frame Coupler part # CA5100B then yes, the Master Lock Heavy-Duty Coupler and Latch Lock Combo part # 3784DAT should work for you as that is what it is primarily designed to fit. I have attached a review video on a straight trailer coupler but it will also work on a-frame trailer couplers as well.
    view full answer...

  • Will Master Lock Heavy-Duty Coupler and Latch Lock Combo # 3784DAT Fit a Bulldog Trail Coupler
  • I have linked the review video for Master Lock Heavy-Duty Coupler and Latch Lock Combo # 3784DAT. It is on the right side of the page. The coupler lock works with Reese, Fulton, Valley, Atwood, Shelby, Putnam, Bulldog, Dutton-Lainson, and UFP couplers. But if you have a special type of coupler it may not be compatible. I have included a link to all of the Bulldog couplers we carry. If you can tell me which one you have, or the same style as the one you have, I can determine if the Master...
    view full answer...

  • Does Masterlock Coupler Lock 3784DAT Fit UFP Couplers
  • Yes, the MasterLock coupler lock part # 3784DAT is a fit for the UFP couplers. It comes with a special insert to use with this style of coupler as well. I attached a review video for the lock for you to check out as well.
    view full answer...

  • Can an Additional Latch Lock Keyed to Match Lock Set 3784DAT be Ordered
  • We may be able to accommodate you. You would need lock # 2847DAT. To get it keyed the same as lock set # 3784DAT we would physically have to pull the matching one from inventory. There is no guarantee that we will have that number in stock. But in order to start the ball rolling you will need to call customer service at 800-298-8924 and explain that you need # 2847DAT keyed to match the # 3784DAT lock set you already have.
    view full answer...

  • Does Masterlock Coupler Lock Set 3784DAT Come with Lock to Secure Coupler To Hitch Ball
  • The pin lock that comes with the Master Lock Coupler lock set part # 3784DAT that you referenced is designed for locking trailers with trigger style couplers to hitch balls. If that's the style of coupler you have this would work well. If you check out the picture I attached you can see the pin lock in place. If the coupler was connected to a hitch ball it wouldn't be able to be removed unless the pin lock was removed since the trigger couldn't be raised.
    view full answer...

  • Recommendation of Trailer Coupler Lock to Fit a Titan 2-5/16 Inch Coupler
  • The Master Lock Universal Trailer Coupler Lock, part # 379DAT, you have referenced will fit a 2-5/16 inch trailer coupler. I also have the Master Lock Universal Heavy-Duty Trailer Coupler and Latch Lock, part # 3784DAT, which is the similar surround lock that goes over the front of the coupler, but it will also include a latch lock that can be used to lock the latch on the coupler for twice the security. Another coupler lock that is one of our top sellers is the Fastway Universal...
    view full answer...

  • Recommended Coupler And Latch Lock For Boat Trailer
  • For your boat trailer, I recommend the Master Lock Heavy-Duty Coupler and Latch Lock Combo for 1-7/8", 2", 2-5/16" Couplers # 3784DAT. This lock will give you a keyed alike lock at your coupler as well as at your hitch ball latch. This combination will deter theft and give you a secured trailer. I've attached a video of this installation for you.
    view full answer...

  • Recommended Trailer Coupler Locks for Wide Coupler Security
  • For your Atwood Channel Tongue Trailer Coupler 80060, I recommend the Fastway Universal Trailer Coupler Lock for 1-7/8", 2" and 2-5/16" Couplers # DT25013 or Master Lock Heavy-Duty Coupler and Latch Lock Combo for 1-7/8", 2", 2-5/16" Couplers # 3784DAT are both good options. The latter doesn't have any restrictions of the width of the coupler.
    view full answer...

  • Recommended Trailer Coupler and Locks for Rollback Car Trailer with 3 Inch Tongue
  • The only 3 inch hitch lock we currently have is the Weigh Safe Hitch Receiver Lock for 2", 2-1/2", and 3" Hitches - 3-1/2" Span # WS05. This will secure your 3 inch x 3 inch receiver tube and accessory. For a jack, you can use the Round Snap Ring Swivel Jack w/ Footplate - Bolt On - Black - Topwind - 10-1/2" Travel - 2K # TJBB-2001-B. If I undersand your issue, it sounds like you need the Titan Zinc-Plated Straight-Tongue Coupler - 21,000 lbs # T4853100 for a heavy-duty trailer coupler...
    view full answer...

  • Dimensions of Master Lock Heavy-Duty Coupler Lock # 3784DAT
  • I went out to our warehouse to take a look at the Master Lock Heavy-Duty Coupler and Latch Combo # 3784DAT referenced in your question. I measured an overall height of 4-1/2 inches and a width of right around 3-1/4 inches. The inner depth of the housing is 3 inches. I have attached an image with these dimensions labeled that you can also check out. This coupler lock is designed to fit almost any 1-7/8 inch, 2 inch, and 2-5/16 inch ball coupler. I have included a short video demonstration...
    view full answer...


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Info for this part was:

Photos by:
Theodore B
Expert Research:
Michael H
Expert Research:
Jameson C
Video by:
Patrick B
Installed by:
Matthew K
Video Edited:
Mike H
Photos by:
Amber A

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