MONSTER® UC1500 SERIES GENERAL PURPOSE WHEEL CHOCKS for ground vehicles are manufactured with highly durable, lightweight polyurethane and are 3rd party tested, certified, and trusted by fleets globally. These chocks are ideal for use with over-the-road trucks, trailers, pickups, and utility vehicles. Rated for vehicles with tire sizes up to 35 in. (88.9 cm) diameter, and gross vehicle operating weight up to 60,000 lbs. (27,273 kg) for the UC1500-4.5, and up to 70,000 lbs. (31,818 kg) for the UC1500-6. UC1500 Wheel Chocks are available in singles or pairs (pairs of wheel chocks are attached with a 48″ long piece of 5/8″ Nylon rope between the chocks).