Ultra-High Security Coupler/Hitch Trailer Lock: This strong and straightforward trailer coupler/hitch lock is designed to secure the common bumper pull trailer. Heavy Duty Trailer Security: This no-nonsense coupler/hitch trailer lock is constructed of 3/16" fully welded cold rolled steel and is bolt cutter and crowbar proof! The surround hasp application accepts most "puck" style locks and provides additional safety and security. Bright Yellow Powder Coat Finish: We believe in presenting a hard target that is why we use a bright yellow powder coat to warn off would be thieves. Coupler Fit: Make sure to double check your trailer coupler/hitch. This lock only fits the coupler/hitches pictured. Ft. Knox Locks: We are a family run and operated small business with our locks designed and proudly made in the USA. High Security Puck Lock: Cobra SideWinder have extreme picking resistance, limited key blank access and over 250 million key code combinations available. Each Cobra SideWinder lock has 10+ combination locking plates each containing multiple anti picking grooves. The locking plates align with a sidebar to keep the inner cylinder engaged with the shell in the locked position. SideWinder locks have a Symmetrical key that will work in either direction, making this a very user-friendly lock. 3/16 welded steel construction with a no-nonsense design which fully encompasses coupler head of the Curt and some similar couplers. Accepts most all "puck" style locks ) which by design are completely bolt cutter proof. Time, noise, power tools or a cutting torch will be required to defeat our lock design which will eliminate most theft interest. If your coupler does not look EXACTLY like one of the couplers in the pictures DO NOT ORDER without contacting us first. Please call us for clarification if you have any questions. Made in America!