Vantech Black Aluminum Clamp-On Cargo Rack System Chevrolet Express 1996-current 155" WB / Extended Model H1506DD04BVantech Black Aluminum Clamp On Cargo Rack System Chevrolet Express 1996 current 155" WB Extended Model H1506DD04B The DD configuration utilizes a 40 degree angled faceplate for both the front and rear end. The angled front faceplate acts as a wind foil, and reduces drag as well as wind noise when traveling. It also channels air over and around any low profile cargo like ladders and folding tents. The rear angled faceplate reduces drag and wind noise