Ancra Trackstar Wheelchock is patented lock and load system using high strength aircraft style track provides positive attachment to your bike hauler. Designed to fit front tire 3.5 inch to 5.5 inch wide. Reinforced, powder coated tubular steel, solid base plate, and aircraft style fasteners provide superior strength. To install, simply position chock stud feet into track, press down and slide chock forward. To remove, simply pull up on the top mounted plunger and slide chock out of the track. No tools required. Designed to fit standard truck beds and flat floor trailers.