PMD Products RV Camper 4" or 4-1/2 Bumper Mount Hitch Receiver Adapter for Bike Toter Cargo Rack Steel construction works on 4" or 4 1/2" square RV Bumpers Reinforced tube ends, Powder-coated rust resistant finish, Zinc Plated Hardware 2" Receiver Tube accepts bike racks, toters, cargo racks etc etc 4 welded-in gussets, 5/8" pin hole with noise reducing bolt NOT FOR TOWING only for accessories