3/16 welded steel construction with a no-nonsense design which fully encompasses one of the set bolts on the drop tube of a gooseneck coupler. You only need protect one of the set bolts to prevent removal.  Accepts most “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. We also sell a few different brands of the “puck” style locks 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.