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Master Lock Trailer Coupler Lock - 1-7/8", 2" and 2-5/16" Ball Couplers
(918 reviews)
Price: $35.35
In Stock
Master Lock
Master Lock Trailer Coupler Lock - 1-7/8", 2" and 2-5/16" Ball Couplers
In Stock
$35.35
Retail:$44.57
You Save: 21%
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- Reviews (918)
- Q & A (0)
- Photos
Master Lock Trailer Tongue Lock
- Fits 1-7/8 Inch Ball
- Fits 2 Inch Ball
- Fits 2-5/16 Inch Ball
- Keyed Unique
- Surround Lock
- Master Lock
- Universal Application Lock
Keep your trailer safe from towaway theft with this universal coupler lock. Its tough frame fits in and around most 1-7/8", 2", and 2-5/16" ball couplers; and it has a bright red color and heavy-duty construction to deter theft.
Features:
- Heavy-duty coupler lock deters trailer theft by preventing hookup
- Large size and heavy weight defend against attempts to break or shatter lock
- Wafer-tumbler lock mechanism resists picking and prying
- 1-Piece housing slides to fit tightly around your coupler
- Powder coat resists rust and corrosion
- Red color provides a visible theft deterrent
- 2 Keys included
Specs:
- Application: most 1-7/8", 2" and 2-5/16" couplers
- Fits standard lip, rolled lip, straight lip, surge brake, hammer blow, and UFP couplers
- Limited lifetime warranty
Note: This product cannot be keyed alike.
Instructions for Locking the Trailer Coupler
- Insert key and turn clockwise to unlock.
- Pull the ball out from the lock body as far as it will go.
- Insert the ball of the lock into your coupler's ball socket.
- Push the lock body in so that it surrounds your coupler.
- Turn key counterclockwise to lock.
389DAT Master Lock Universal Trailer Coupler Lock - 1-7/8", 2" and 2-5/16"
Item # ML389DAT
Customer Satisfaction Score:
99% were satisfied with this product
1% of customers were not satisfied
- etrailer mistake
- Product did not meet expectations
- Wrong item was ordered
Ratings & Reviews
4.8
918 reviews
by:
Raymond
06/02/2025
Great product. Solidly built, simple-easy to use. I'm using it to protect a 6x10 hydraulic dump trailer that I'll leave parked in an isolated and wooded area on my farm to haul firewood and wood chips. I don't want the trailer to disappear. I have a wood splitter that I want to protect, too, so I'll be purchasing another coupler lock.
by:
TM
10/07/2026
Love this lock! My old one was difficult to use. This one is super easy and works great! This will fit a wide variety of couplers.
by:
Douglas
12/15/2019
Recently bought a boat and the trailer did not have any way to lock the tongue that I could see. After seeing that my stepson had a trailer with this style lock on it and seeing that it would be virtually impossible to pry it off I did some research. I have purchased from etrailer in the past and trust them to only sell the best. I ordered it and received it in a timely manner. It fits perfectly and I now feel my trailer and boat are secure. Who would doubt the Master Lock brand anyway!?!
Douglas
12/16/2020
Still working great, no complaints here.
by:
Li Zhang
01/20/2019
It's a great product. It looks good on the trailer, and you can see it from very afar. And there is no way to saw it off, break it apart, or something like that. The construction is basically rounded, and there is nowhere you can find a starting point to place a saw or breakaway device on it. I have also bought different lock from Reese, and it looks wimpy, and easy to take it apart, or saw it off as some reviews have suggested. It's also easy to put it on and take it off. Just love the product. Here I attach some pictures in the campgrounds, etc.
by:
Meg R.
06/13/2026
Amazing customer service, great quality items, reasonably priced. Love this company!
by:
Robert
01/14/2018
I feel much better about parking my trailer on the street with this lock on the hitch. Not only does it lock up the hitch securely but the bright red color signals to prospective thieves that this trailer cannot be towed.
It is easy to attach and easy to remove. Also very compact so it can be stored easily. The shipping time was less than I expected. etrailer.com is my goto supplier for my trailer accessories.
It is easy to attach and easy to remove. Also very compact so it can be stored easily. The shipping time was less than I expected. etrailer.com is my goto supplier for my trailer accessories.
by:
Kevin
03/20/2026
Great sense of security. Easy to install/remove. It fits various trailer ball sizes.
by:
Larry Simon
09/23/2016
I received the Master Lock Trailer Coupler Lock that I ordered. It was delivered in just a few days just a it was supposed to. It is exactly what I was looking for. It will help detour anyone from stealing my trailer ! I am extremely happy with the lock and etrailer ! I think this is a great company with great pricing on there products ! I will recommend them to everybody and will be ordering with them again real soon ! It was an easy and excellent experience. Great customer service too ! Thanks etrailer !
by:
brandon
08/25/2016
This is a terrific design since unlike padlocks, can't easily be cut with bolt cutters. I like the bright red color which tells a thief there is a lock to deal with from a distance. I think someone who wants your trailer can probably defeat any system you use, so the goal is to make it tough as possible and I think this lock does that.
by:
Thomas M.
07/06/2018
Works well I like the fact that it`s easy to connect, fits 1-7/8" ball up to 2-5/16" and protects my trailer peace of mind
by:
Erik A.
05/13/2023
Great locks!! I feel a lot better leaving all three of my trailers at home with these locks on my trailers! Definitely recommend!
by:
Fred
08/01/2026
Return policy sucks! Done with your company
by:
Thomas
09/12/2025
Fits well and much more affordable than other like products.
by:
John
04/09/2025
Looks good. Might change tumbler to make it harder to pick.
John
4/10/2026
Pretty good. Seems more like a deterrent than a heavy duty lock. So far, so good.
by:
Mike W.
08/21/2019
I installed this trailer lock as soon as I purchased it. All I have done is spray the lock with WD40 a couple times and the lock has protected my favorite boat with NO problems at all.
by:
Robert
03/14/2026
It's red and it works. I now sleep better at night knowing my beautiful utility trailer is protected.
by:
George
11/12/2025
Really like the way it fits in the trailer coupler,locks down securely,and the key lock seems real positive
by:
Robert K.
07/27/2025
This is an excellent lock for a hitch. It's easy to put on and take off. I use it on my travel trailer when we go camping. I have another one for my hauling trailer. I would recommend this product as it works well.
by:
David
07/09/2018
This is just the anti-theft deterrent device we have been looking for. We have an Excavation business and keep a lot of expensive tools and equipment in a 6x12 trailer. We can sleep at night knowing our trailer will still be there in the morning. This thing is very easy to put on and take off.
by:
Michael
11/19/2019
Nice tool, I like that it will adjust easily for different depths so it will fit more than one size trailer tongue. It pulls in snug and with a couple firm smacks with a 2 pound hammer is still works just fine.
by:
Chase
06/01/2021
Great product. Master Lock brand and quality. Very secure and provides me with peace of mind that it’s a huge deterrent to would-be boat thieves.
by:
Peter
07/27/2025
Installs easily, Fit is kind of loose on a 2 inch tongue coupler. Color does make it obvious so may provide a visual deterrent against opportunistic theft.
by:
Greg V
09/30/2017
Nice lock. It’s nice that there is nothing to really cut on it. Latches on nice and strong. Easy to use. You could even use a default latch lock with it. Hope it holds up as good as it looks. Will review again after awhile.
by:
Logan L
03/21/2019
Needed something to help those thieves from having an easy hook up to my new cargo trailer. This affordable and sturdy tongue lock fits perfect, arrived as stated, and makes me feel that anyone wanting an easy hook up onto my property would at least be slowed down by this effective and easy to use device. I also have an axle wheel lock and GPS tracking on the trailer that stores and transports my four dirt bikes valued at around $26K, plus the $5k trailer. Given an adequate amount of time....i'm quite certain this inexpensive addition will counter attempts at the low hanging fruit for easy picking by low life's looking for the easy score. not today my friends. Its sturdy, easy to install, and looks good and visible to intruders.
Logan L.
3/22/2020
I have to say, that after a year, my property is still safe, and I have the assurance that I feel confident it will remain. In all weather conditions, the lock still works great, paint is a bit faded, but Im getting grayer too!! Great product, easy to use, and relieves some unneeded worries!!Always have had good dealings with etrailer.
by:
Chad
09/07/2025
Works as designed and very well. Would buy again Lock cylinder doesn’t take key as easily. That could be my problem.
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view full answer... - Replacement Keys for Master Lock Trailer Coupler Lock 389DATIf you know the key number that came with your Master Lock Trailer Coupler Lock # ML389DAT then all you need to do is order the Replacement Key for MasterLock Coupler Locks # MLK1, and be sure to input the correct key number on the page prior to ordering. If you don't have a record of your key number then you'll either need to call a locksmith to make a copy for you, or you'll need to order a completely new coupler lock, and you'll want to record the key numbers once you get it.
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view full answer... - Can the Master Lock Trailer Coupler Lock Be Re-Keyed Before it is Shipped?I really wish we could rekey these because we get the request all the time but we just can't do it. I have reached out to Master Lock on this subject before and they have told me you can take the Master Lock Trailer Coupler Lock item # ML389DAT to a lock smith and have it rekeyed yourself but they won't do it. If you are looking to purchase multiple coupler locks that can be opened with the same key I recommend the Fastway Universal Coupler Lock for 1-7/8", 2" and 2-5/16" Couplers - Key...
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Brooke M.
6/5/2025
Yeah I hear you, Raymond! A little peace of mind about your trailer's safety I'm sure goes a long way. Especially when it's for a trailer it sounds like you get a lot of use out of. What kind of farming do you do?