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  1. Trailer Tongue Lock
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  3. Fits 2 Inch Ball
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  5. Keyed Unique
  6. Cast Iron
AMPLock Coupler Lock for Flat Lip 2" Ball Couplers - Ductile Cast Iron

AMPLock Coupler Lock for Flat Lip 2" Ball Couplers - Ductile Cast Iron

Part Number: AMP89FR
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Trailer Tongue Lock
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Use this heavy-duty cast iron coupler lock to help prevent trailer towaway theft. Fits standard 2" ball couplers with flat lips. Resists picking, cutting, drilling, and freezing. Tumbler offers nearly 1 million possible key codes. Great Prices for the best trailer tongue lock from AMPLock. AMPLock Coupler Lock for Flat Lip 2" Ball Couplers - Ductile Cast Iron part number AMP89FR can be ordered online at or call 1-800-940-8924 for expert service.
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  • Reviews (95)
  • Q & A (0)
  • Videos (1)
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AMPLock Trailer Tongue Lock - AMP89FR

  • Fits 2 Inch Ball
  • Surround Lock
  • AMPLock
  • Keyed Unique
  • Cast Iron
  • Universal Application Lock
  • Flat Lip Style

Use this heavy-duty cast iron coupler lock to help prevent trailer towaway theft. Fits standard 2" ball couplers with flat lips. Resists picking, cutting, drilling, and freezing. Tumbler offers nearly 1 million possible key codes.


  • Tamper-resistant, sturdy lock deters trailer theft by preventing hookup
    • Fits over coupler, engaging it like a trailer ball does and blocking the ball opening
    • Prevents would-be thieves from hitching your trailer to their tow vehicle
  • Push-and-lock cylinder locks without the need for a key
    • Lock's location on bottom makes it difficult for thieves to access
  • Rotating-disc-tumbler lock provides maximum security
    • Nearly a million possible key codes
    • Resistant to picking and drilling
  • Heavy-duty ductile cast iron construction
    • Absorbs shock to prevent breaking
    • Resists any kind of cutting, including cutting with a torch or liquid nitrogen
  • Molded fit with swivel design decreases hold options for thieves
  • E-coat finish resists corrosion
  • 2 Keys included


  • Application: standard ball couplers for 2" balls
    • Coupler must have flat lip
    • Maximum coupler width (including lip): 4-3/8"
    • Maximum lip thickness: 7/16"
    • See below for examples of couplers this lock will work with
  • Lock pin diameter: 7/8"
  • 5-Year limited warranty

Coupler Fits:

This lock fits 2" ball couplers with a flat lip. Examples of some of the couplers it fits are pictured below.

TLS2 coupler applications

Secure Locking Mechanism

This coupler lock has a disc tumbler locking mechanism. Unlike locks that use vulnerable spring-loaded pins, this ultra-secure lock is bump-proof. The cylinder has a series of rotating discs that can be correctly lined up only when you turn the corresponding key. Two identical notched keys are included to operate the lock. Because these keys feature 1 of nearly a million possible key codes, it's extremely unlikely that another individual will have a key that can open this lock.

U-TLS-2 AMP Lock Boat, Trailer, and RV Coupler Lock for 2" Ball Couplers with Straight Lip - Ductile Cast Iron

Video of AMPLock Coupler Lock for Flat Lip 2" Ball Couplers - Ductile Cast Iron

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

Video Transcript for AMPLock Flat Lip 2 inch Ball Coupler Lock Review

What's up, everybody It's AJ with Today, we're gonna be checking out this AMPLock coupler lock. It's going to fit on your trailer couplers that have the flat lip around there, and it has a two inch coupler on it. And what it's going to do is, it's gonna take up that space down here, so that nobody can mess with this when you're not around. So it's on there right now. Nobody can back up there and hook up to your trailer.

It's gonna prevent people from trying to use tools to get at it. You can see that this doesn't leave a whole lot of space to get in there and mess with anything. And most likely, they're just going to go to the next trailer that doesn't have any protection on it. Let's check it out. This lock's a little different from the other AMPLocks, the other ones have the second piece.

That's going to be the two inch ball that would fit up in this coupler and take up that space. Now I do like that style, because it doesn't leave any space in here. This one just has a pin that pops up and keeps it from coming off. So let me slide it back on there and show you. You just match up the grooves here with the flat lip.

It sits on there and you can just push that up, and now it's locked. That pin is now all up here and locking it tight. Another thing I want to point out, is this rounded plate here, it extends out just a little bit. And what this is going to do, is completely cover the portion underneath the coupler where their ball would be. That goes with the other one, having that complete ball in there.

This one has this plate to cover up that spot, so once it's up and on there, slid in, there's no access point to mess with it. Underneath, you can see the lock is a rotating disk tumbler, which is going to be resistant to drilling and lock picking. It also comes with two keys that are really easy to use. They go right in there and work really well. The whole thing's going to be cast iron and shock-absorbent. So that means if somebody was to hit it with a hammer, it would absorb that shock and not have any issues. Something else I would recommend getting is a coupler latch lock. It would feed in right here and lock up this latch, so that it can't be tampered with when you're not around either. Some things to consider before you order, is make sure it's going to fit on your trailer. It's going to fit a coupler width including the lip, of 4 3/8 of an inch. And then it's going to fit with the thickness of the lip, of 7/16 of an inch. Overall, I think it's gonna be a good addition to your trailer. Never hurts to keep it locked up when you're not around. Well, thanks for hanging out and I hope this helped..

Customer Satisfaction Score:

Customer Reviews

AMPLock Coupler Lock for Flat Lip 2" Ball Couplers - Ductile Cast Iron - AMP89FR

Average Customer Rating:  4.8 out of 5 stars   (95 Customer Reviews)

Use this heavy-duty cast iron coupler lock to help prevent trailer towaway theft. Fits standard 2" ball couplers with flat lips. Resists picking, cutting, drilling, and freezing. Tumbler offers nearly 1 million possible key codes.


It is a little large for my 2", it fit my trailer with a 2 1/2" coupler, I wouldn't get another one.


Kate was extremely professional and knowledgeable about the trailer coupler lock that I needed. She was very efficient and helpful in placing the order and when the lock arrived it fits perfectly. It is on my trailer right now and is exactly what I needed thanks to Kate and her performance. Give her a big monetary raise and recognition before her peers.


This lock is a solid and hefty piece of equipment. Make sure to get the right model for your set-up. The width of the lip on my trailer was 3.75” and the lock fits like a glove.


Has worked flawlessly for over a year stored outdoors in Chicago. Finish seems to be holding up and the action still works smooth. This is a very robust design that would be difficult to defeat.


I just got this new lock and have no long term experience. However, I have used and handled a lot of the so called locks on the market and I can tell you they’re cheap garbage. This lock weighs in at several pounds, and is a solid piece. The lock bolt action is smooth and comes with 3 keys. Installed on the trailer the fit is snug with no extra movement or sloppiness. I’m very impressed and feel good about this lock.


Seems like a great lock. Beefy lock and nice fit on my travel trailer, plus it is very simple to install and remove.


well, nobody has has tried to put a sledgehammer to it in the middle of the nite yet,but from the looks of it, I don't think it would hurt it much anyway. I like the design, an it looks very strong,an so far I'm happy. I like the way it locks.


It was all that I expected strong and heavy duty. I will fish at ease knowing I have this lock on my trailer.


Arrived very quickly and is very HEAVY duty.
work great so I can relax.


Best service,also good hitch lock.


It's terrific!


You guys always have everything I need. Always quick on your shipping.


these are the best locks ever and locks can be keyed the same.


Easy to install. Does the job!


well made. works very smooth. strong.






Good tight fit, tough construction, and a disk core. It has sat out in the elements it's whole life and the lock still spins like new. I did drop the ball portion with the key still in it and it bent the key. That's my fault though. I Like the lock.


Impressive lock. Well machined.
I was
disappointed I couldn’t engage ball with the hitch ball clamp assembly after the flange lock was installed.


This is a nice lock, but there is plenty of room between the lip of the lock and the body of the trailer coupler for a prybar to be used. The coupler does have quite a bit of 'play' when installed - probably because it is a universal lock and as such it is designed to accommodate the dimensional differences between coupler manufacturers. Overall, the quality is very nice, and I have some ideas regarding how to 'tighten' up the fit between the lock and the coupler via shims. The manufacturer should consider including some shims - which could be used to provide a better fit between the lock body and the coupler.


Trailer still where I parked it. This lock is doing its job.


This is the best trailer tung lock I have ever used. Heavy duty, well built, with a very unique key system that was well thought out. YES, I would highly recommend the AMP LOCK SYSTEM FOR YOUR TRAILER. YOU WONT BE DISAPPOINTED.


Does its job as advertised. I leave this trailer on construction sites, and no attempted thefts yet.

Show More Reviews

See what our Experts say about this AMPLock Trailer Tongue Lock

  • AMPLock Trailer Coupler Lock Suggestions For A 2022 Jayco Jayfeather 25RB
    Depedning on what your trailer has we may have what you need. If your trailer has an underslung 2-5/16" ball coupler # AMP56FR is a great option. -If you have a flat lip 2" ball coupler, then the AMPLock Coupler Lock for Flat Lip 2" Ball Couplers # AMP89FR is a great option. -If you have a rolled lip 2" or 2-5/16" ball coupler, then the AMPLock Coupler Lock for Rolled Lip 2" or 2-5/16" Ball Couplers # AMP29FR will work great. Finally, if you have a 2" ball coupler without a lip, the...
    view full answer...
  • Recommended Trailer Coupler Lock for 2 Inch Coupler
    Thank you for the pictures! This helps a great deal when making sure parts are compatible. The AMPLock Coupler Lock for Flat Lip 2" Ball Couplers - Ductile Cast Iron # AMP89FR you were looking at is a great choice for your 2" coupler and will give you superior security for your trailer. I've linked a review video of this lock for you to check out, as well
    view full answer...
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  • Solution for Replacement Key for Fulton Coupler Lock
    Depending on the style of key you may be able to have a copy made. Outside of that option, there are no replacement keys available for your Fulton lock with a 605 key. If you lose your other key the only option would be to replace the lock with one like the # 63228 or # AMP89FR you were looking at.
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Do you have a question about this Trailer Tongue Lock?

Info for this part was:

Employee Andrew K
Installed by:
Andrew K
Employee Lindsey S
Written by:
Lindsey S
Employee Chris R
Video Edited:
Chris R
Employee Wilson B
Updated by:
Wilson B
Employee Aidan B
Video by:
Aidan B

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