The Rock Solid is the effective way to reduce the costly damage that road debris cause to your towed vehicle. Made of durable, all-weather resistant TPR (thermoplastic rubber) material that allows air to flow through the vented flaps, but sturdy enough to stop rocks or small road debris. The two-piece design is fabricated in flexible strips of material attached to a steel angled channel. Both models mount installs on the hitch insert of most 2" receiver hitches and slides on and off for easy removal when not towing. * All brackets, hardware, mounting bar are included in both kits.