These pucks attach the Old Man Mountain rack frame to your road, gravel or cross bike fork. They provide a secure upper attachment point for the front 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 forks. Slots in the puck also allow for use with metal hose clamps (not intended for carbon forks). Pucks can be left on the bike for future reinstallation of the rack.