Amplock is a highly rated trailer coupler lock. After having a trailer stolen, I’ve come to trust these super duty units. I’ve used a bunch of different types. Wheel chocks, chains, cheap coupler locks and none stack up to these! These use two code cuts in the keys, making them near impossible to pick and duplicate. You must have both numbers to get duplicates/spares. You can register your key number/code with Amplock, so they have them on record and can order keys if they become lost.These locks are not cheap, but I feel they are worth every penny. Check Amplock out, then come get one from me. Please look at the photos to make sure these will work for you. These sell for $265 new. I have two new: BRP-2516 for 2 5/16 balls. I have one BRP-2 for a 2” ball. $150 each, firm.