3/16 welded steel construction with a no-nonsense design that fully encompasses the ball head of a Curt Heavy Duty Adjustable coupler. Accepts most all “puck” style locks (sold separately) 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. Be sure to compare your coupler to the pictures here and contact us first before ordering for confirmation  We also sell a few different brands of the “puck” style locks (sold separately) with varying levels of security. DO call us for clarification if you have any questions. Be sure to check out our installation video HERE. We offer discounts starting at 10 or more Ft. Knox Locks. Made in America!