Threaded 1.25 inch receiver trailer hitch lock is great for locking your bike rack to the hitch. Hitch lock has a 1/2 inch diameter and works for all 1.25 inch receivers. This lock is for class I, II, III or class IV receivers. Threaded bolt provides the anti wobble needed to keep your trailer or bike rack secure. Comes with 2 keys. It has a covered key opening and key insertion and removal is easy. It is a weather resistant lock..