Roadblocks All-Terrain Urethane Wheel Chocks are specifically designed for use on fire equipment. They comply with NFPA 1901-1904 and meet SAE-J348 standard for up to 32 inch and up to 44 inch wheel diameters. These tough, damage resistant polyurethane chocks are resistant to oils, fuels and solvents, and feature high strength aluminum base plates with posi-grip traction cleats or anti-slip rubber traction pads. For added safety and convenience, Checkers incorporates a molded carrying handle and safety colors for easy identification.