The etrack O-Rings are compact and portable, compatible with all E Track/X Track trailer tie-down rails or E port single slots. The O-ring could be used with any straps, ropes, bungee cords, chains, etc. Each slot has a breaking strength of 4,500 pounds and a safe working load limit of 1,500 pounds. For cargo management in Trucks, Cargo, Bikes, Boats in Trailers, Trailers, Motorcycles, Vans, Warehouses, Docks, Marinas, Pickups, Flatbeds, ect.