Trailer Coupler & Safety Chain Lock — 2 or 2-5/16 in

Just as nice as the other one that is 3 times the price. I have the Proven brand. This one is perhaps 1/32 thinner steel, but it really doesn’t matter.

This is very nice, and I like the spring loaded lock mechanism. The keys are a funky shape, but doesn’t seem to make it any more difficult.

There are many of these types of locks on Amazon. I landed on this one because of the reviews. It wasn’t the cheapest or the most expensive one. It arrived on time well packaged.
Unboxing revealed it came with 5 keys, an instruction sheet. This lock is heavy duty. It also has provision to lock up your safety chains. The lock worked smoothly and seemed to be of good quality. Pleased with fit an function of this lock.

Just received my lock very very well built and tough. I have high hopes for this lock. Also if you put the chains inside it reduces the shakiness of the rock it makes it more tight for a better secure hold on your trailer.

Looked well built, however, Doesn’t fit, lock won’t engage

i wanted the lock to cover the couple pin latch to consolidate how many locks you needed but after playing with it it’s fine. I was able to get 2 thick chains to weave through which makes the lock much more sturdy. I do agree the puck lock is really light aluminum and I will probably upgrade that soon. Overall a great deal at half the price of a proven industries lock

Seems like a nice sturdy build quality, but it doesn’t fit securely. It would be very easy to remove without unlocking it.

As a busy mom new to owning a boat trailer, I was honestly clueless about choosing the right lock. So many options looked the same online, but the prices varied wildly—some felt downright unreasonable. After reading mixed reviews (yes, I saw the ones about missing keys or fit issues), I nervously ordered this one, hoping for the best.
When it arrived, I held my breath opening the package. First thing I noticed: three spare keys (hallelujah—no frantic key hunts before trips!). The lock itself has a rugged, industrial feel—thick metal casing with zero flimsy parts. It's heavy enough to feel theft-deterrent but not awkward to handle. Slid it onto our trailer hitch, and it clicked into place securely.
I won't lie—I'd read about complaints like keys not working or sizing problems, but luckily, everything worked smoothly for us. The key turned without fuss, and the lock sits snugly. Is it as flashy as those high-end locks costing triple the price? Maybe not, but it's sturdy, straightforward, and does the job without overcomplicating things. For the peace of mind it's given me? Worth every penny.

Source disclosure: Amazon Vine review of a free product.

If you are like me, then you don’t want someone you don’t know taking your trailer. You built it yourself, and it’s nearly irreplaceable. OK, maybe you are just a little like me. I haven’t bothered with other locks as they are pretty useless. One of the common style locks from a name brand, I defeated in under 3 minutes with minimal noise and in 3 different ways after it wouldn’t unlock for a friend. To me these cheap ones are about as useful as a “caution area under surveillance” but without any actual cameras.

I think I could still defeat this one with an angle grinder or reciprocating saw in under 10 minutes, but it would make a lot of noise. The lock may be the weakest spot, but it is easily upgraded to any standard 2 ⅞” puck lock - and the skies the limit for how nice of a lock you can get.

When I looked at this, I thought it might be a plastic shell, but that is not the case - it’s actually ¼” thick metal! A few other dimensions for you for the 2 5/16” model - the main shell is 5” inside diameter, the puck lock inside diameter is 3”. It is about 0.47” for the pin hole - which on the included lock is tapered at the end to make it lock easily. The pin hole is actually oblong as well, which does give the lock a bit of a looser feel, but doesn’t affect its security in any way I can see. The included puck lock is 2.82” in diameter with a pin just under ⅜” (/9.78 mm).

I like that the puck lock is protected from the top from the elements, and the key faces down, which should keep it clean and dry in most cases. Again, the lock doesn’t appear super high quality - but I’m not a lock expert either. I do appreciate the curved key, which likely gives it a little more rigidity if your tumbler doesn’t want to turn in the cold.

My trailer frame comes right up to the hitch - again being homemade. Despite this the lock still goes on all the way (with some room to spare). It fits my coupler quite tightly. I may be able to wedge my chains in there, but they are large hooks and larger chains than most, so I choose not to.

Side note: I actually built myself a similar lock for a 2” coupler. I had quite at least half a day into it, and although its theft resistance is on par with this one, this one looks so much cleaner and more professional. Because of how the tongue tapers on this one I couldn’t utilize the same design, but this one does the job quite elegantly.

No lock is perfect, and I still try to block the trailer in when possible, but I feel a lot more secure about my trailers safety with this lock on it. If you want to take it to the next level - since it is all metal you can (and I might in the future) weld a tab to it, and install a motorcycle lock like this that alarms loudly if it senses vibration.

The key slot is closest to the metal instead of the opposite side. This barely gives you enough room to turn the key. So when you are putting the key in blind from the bottom it’s worse. Not rocket science to put the slot on the other side.

Source disclosure: Amazon Vine review of a free product.

The lock is a solid and heavy-duty option for securing my trailer. Right out of the box you can feel how heavy sturdy and sturdy it is, with a durable metal construction that gives me confidence in its ability to deter theft and mill make it difficult for anyone doing a destructive drill method to unlock it. It fits my 2-5/16 inch ball coupler perfectly, and the added feature of securing the safety chains is a nice bonus for extra protection.

However, while the overall build is impressive, the lock mechanism itself feels a bit loose. It doesn’t feel as snug or secure as I would expect from a high-quality trailer lock, which raises some concerns about long-term reliability. That being said, it still locks properly and serves its purpose, but I would have liked a tighter, more secure fit. I also like the one click lock mechanism which makes it super fast and convenient to lock without having to us a key.

Overall, this is a good, heavy-duty trailer lock that provides a decent level of security. If the locking mechanism were improved, it would easily be a 5-star product. Still, for the price and features, it's a solid choice for protecting your RV, camper, boat, or travel trailer.

Source disclosure: Amazon Vine review of a free product.

NiwNiw Trailer Lock,Upgraded Heavy Duty Tongue Hitch Lock Secure 2-5/16 Inch Ball Coupler and Safety Chains,Anti Theft Locking Protection for RV,Camper,Pickup,Boat and Travel Trailer

This feels like good solid quality, a heavy duty hitch lock for our occasional uses. This might not stand up to daily use or a lot of abuse, constantly off and on, but if it’s just for summer boat hitch or trailer hitch use it’s a great choice. At the moment, I’m not sure how well it will stand up to the elements, rain or snow.

After reading other reviews I worried whether the keys would be included and if they were, whether they would work, but happily, 3 keys are concluded and they all work smoothly.

As we’ve never had a hitch lock before, I can’t comment on pricing, but at ~$170 (at time of review) I know there are much cheaper options out there.

Source disclosure: Amazon Vine review of a free product.

Heavy Duty Trailer Lock for $178.98

This lock came in an unmarked cardboard box but was well protected.
It's definitely heavy duty as its very thick metal and weighs in at 10 pounds , 11.7oz .
It's pretty simple to use and it goes on the trailer ok but it is a little wobbly.
The lock comes with 3 keys and they work flawlessly and the lock is very easy to get on and off.

The only difficult part is that the key part is facing down which makes it awkward to get to, but also makes it difficult for a less than honest person as well.

Overall, it's a very solid quality lock for your trailer that I think would be insanely difficult to remove, so I'm sure a would be criminal would not want to even try.

Source disclosure: Amazon Vine review of a free product.

This lock came with keys, but they do not fit the lock. I have another brand one for my hitch lock on my SUV that has the same key blank, but was not lucky enough that it would open the lock either. It seems safe, but it is quite loose and might not work for all hitch tongues the way it is designed. I cannot even try it on mine as I cannot get the lock off.