The Advantage 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.