Reese Towpower barrel-style (dog bone) class V receiver lock is designed with a 3-1/2" span for 2-1/2" square tube receiver hitches. Lock secures class V ball mounts with a 5/8" receiver pin hole. It includes a push-button lock mechanism which makes it easy to secure. Corrosion-resistant chrome construction includes a built-in rubber cap that keeps out dirt. Lock may also be used with class III/IV receivers. Easy to use. Comes with two keys.