The Trimax UMAX100 Universal Trailer Coupler Lock offers an exclusive design that provides 360° of hardened steel protection for your unattended trailer. Get instant security for your camper, boat, or trailer when they are not hooked up to your vehicle. This lock features a 6-tooth, 3/8" dual ratchet locking system, a hardened 5/8" 16mm steel shackle, and 1/2-turn technology that cannot be false locked.• Easy to install â slide hitch ball up into the coupler and replace the U-shaped shackle• 9/16" shackle• 360° of solid hardened steel protection• Patented dual purpose coupler lock• Fits most couplers (1-7/8", 2", 2-5/16")• Ballistic-grade nylon housing absorbs hammer blows and protects against weather• Includes two keys Hardened 5/8"" 16mm steel shackle Half-turn technology cannot be false locked Fits most couplers (1-7/8"", 2"", 2-5/16"") | Trimax UMAX 100 Universal Trailer Coupler Lock