Saris Tracks System design to bolt to truck beds, inside vans, or utility vehicles.6061-T6 ExtrusionExtruded aluminum base for Traps fork mount and wheel holders (sold separately)Triple Tracks allow the fork and wheel holders to be angled for carrying more bikesStainless steel hardwareTraps have 1.4 x 4.2" contact area, anti-rattle design, mounting bolts come with Tracks system