Smart Solutions Rock Solid Tow Guards for Trucks (2-Pack)Category: Hatch Guard RailRock Solidâ¢ is a full width protective tow guard which prevents rocks, and road debris from causing scratches, chips, and dents to your boat, camper, or motor vehicle during towing. Slides off for easy access to spare tire. Rock Solid is made of durable, all-weather resistant TPR (thermoplastic rubber) material. It provides solid protection to towed vehicles from flying road debris. The two-piece design is fabricated in flexible strips of material attached to a steel angled channel. Includes 2ea of the sizes listed. Truck model installs on the hitch insert of most 2" receiver hitches and slides on and off for easy removal when not towing.