Demco 6333 - 21K 5th Wheel Rail Adapter for Chevrolet/GMC Silverado/Sierra 2500/3500For Chevrolet or GMC trucks with OEM underbed base rails and 6 1 2' or 8' beds Converts your factory installed, underbed 5th wheel mounting kit from Chevrolet or GMC to standard above bed rails Lets you use your 5th wheel trailer hitch that attaches to standard, above bed rails Mounts to OEM pucks (or sockets) in your truck bed Unit drops into pucks and locks in place No drilling or welding required Rust resistant black powder coated steel