A no nonsense Approach To Trailer Security!!! This lock fits only the 2" & 2 5/16" Ram forged steel sliding collar coupler including the adjustable version which is very similar to the Bulldog coupler lock except the hole is slightly larger. Made with 3/16" fully welded steel with welded hinges and hinge pins. Heavy yellow powder coat finish which screams "stay away". Unlike almost all other locks for this application, this one is Bolt Cutter and crowbar proof, and can only be defeated with power tools or a cutting torch if the thief has time. The surround hasp for "puck" type locks has a proven track record nationwide on construction storage containers for decades. Don't trust your trailer and equipment to just any lock. Think Ft Knox Locks. Watch our lock defeating videos, to see how easy most locks are to defeat - not so with Ft. Knox Locks. The locks are proudly made in the USA and have a Lifetime warranty against manufacturing defects. Powder coat is not warrantied.