This 1762mm/69.4â long, full-size, Slimline II cargo roof rack kit contains the Slimline II Tray, Wind Deflector and 3 pairs of Grab-On Feet to mount the Slimline II Tray to the roof rails of your Mercedes GL. This system installs easily with 4x4 ready feet that grab on to the existing factory/OEM roof rails. No drilling required.