SECURE: Hitch tightener prevents rattling, wobbling, rocking and hitch movement for cargo carriers, hitch racks, bike racks and trailer ball mount brands such as Thule, Rola, Yakima, Inno, Draw-Tite, Hidden Hitch, Reese and StowAway INCLUDED: A heavy-duty 1/2 inch stainless steel U-bolt and 5/16" thick powder coated plate that will stand up to all weather conditions and loads. Easy installation by sliding the U-bolt over the stinger, sliding the tightener plate onto the U bolt, and tightening it in place with the included corrosion resistant hardware. Can be mounted from the bottom if hitch ground clearance is low COMPATIBILITY: Hitch tightener is compatible with all hitch brands, including Curt, Blue Ox, Hidden Hitch and U-Haul, among others, and hitch classes I, II, III, and IV (1, 2, 3 and 4), both 2” and 1.25” models, ideal for hitches on SUV’s, vans, trucks, RV’s, sedans and trailers. SUPERIOR DESIGN: Original anti-rattle hitch tightener design is proven to be one of the strongest and most effective on the market WARRANTY: Manufactured in the USA with a lifetime warranty