KEYED ALIKE - One key opens two locks. Each lock comes with 2 keys, for a total of 4 keys. RECIEVER LOCK FEATURE - The Trailer Hitch Receiver Lock Pin is designed with 5/8" diameter and 3-1/2” long to make it works well with class III IV hitches, big towing vehicle, truck, 2” 2-1/2” hitch receiver. (Please confirm your required size or email us for more suggestion before having the order). COUPLER LOCK FEATURES – Made of premium strength steel and coated with electrophoretic paint, our trailer hitch is durable and rust-proof. It is reliable for long-term hauling and is secure for full protection, safely protecting your trailer, boat, camper and so on from theft. SAFE & EASY TO USE (RECIEVER LOCK) - Our trailer coupler lock is designed for easy operation. With the push-to-lock design, you can easily push to lock it without using key. To open it, just turn the key a little bit and the pin will pop out by itself. And the dust cap aims to keep the keyhole away from water and dirt, great design for easier using. SAFE & EASY TO USE (COUPLER LOCK) - Our coupler locks are easy to operate with screw-type locking action -- just turn the key 5-7 times to open or lock, save your time and effort. The tow hitch can be installed quickly and easily so that you can hoop up and head out right away.