Extreme Max 3004.3156 Straight Base for Slider Trax/OEM Marine Accessory Mounting Systems, 4 Pack For Boats with OEM Rails - The multi-fit design fits most boats pre-equipped with gunnel extrusions like Lund & G3. Works great with Lund Sport Trak. Construction - Bases are made of heavy-duty composite for maximum durability and corrosion-free life. OEM Approved - Available pre-installed on certain model boats from recognized OEM leaders. Options - Slider Trax bases and rails are sold separately to maximize ordering options. Warranty - 2-year replacement warranty.