These pucks attach the Old Man Mountain rack frame to the front or rear of your road, gravel, or cross bike. They provide a secure upper attachment point for the rack. Included in the packet are heavy-duty zip ties, clear protective film, and mounting hardware. Designed for use with carbon, steel, titanium, and aluminum bikes and forks. Slots in the puck also allow for use with metal hose clamps (not intended for carbon bikes). Pucks can be left on the bike for future reinstallation of the rack. Recommended for use only with specific Panduit brand 120 lbs zip ties. Panduit #BT2LH-TL0. - One size fits all road, gravel, or cross bikes. - For use on either rear seatstay or front fork - Made from a carbon resin composite for lightweight strength - Includes heavy-duty zip ties with stainless steel tangs (extra zip ties included) - Includes clear protective film - Hardware included