Trimax UMAX50 The UMAX50 features a rugged corrosion resistant finish. Provides instant security for your camper, boat or trailer when they are not hooked up to your vehicle. Features 1/2 turn technology that cannot be false locked. For dual force security add a TRIMAX chain or cable secured to an anchor point! Also, add a TRIMAX coupler lever lock for additional protection. Easy Installation. Slide ball up into coupler and replace u-shackle. Fits all of the following coupler and more: 1-7/8" or 2" Fulton, Atwood 2", UFP, Bulldog, 2-5/16" couplers, Fulton Heavy Duty, Surge Brake (reverse mount). TRIMAX makes the world's toughest locks. Through value added engineering design, TRIMAX is committed to product innovation that holds up to the hightest quality standards. TRIMAX provides maximum security for marine, trailer and tow, RV, performance truck, power sports and bicycle applications. Tested. Tough. TRIMAX. TRIMAX offers a lifetime warranty on all of their products.