The Checkers™ heavy-duty MC3012 wheel chocks for ground vehicles are manufactured with highly durable, lightweight polyurethane and they feature a larger base that makes them ideal for use with heavy equipment such as haul trucks, loaders, and cranes. MC3012 wheel chocks are for mine haul trucks with tire sizes up to 142″ (241.3 cm) in diameter and gross vehicle operating weight up to 855,000 lbs. (725,748 kg). A maximum rated payload of 240 tons. This chock is designed for normal haul road grades.