AC6856 aviation wheel chocks are 56 inches long and aredesigned for large to over-sized aircraft and aviation equipment. They are manufactured with highly durable, lightweight polyurethane, which lasts longer than wooden chocks, never needs painting and eliminates Foreign Object Damage FOD threats for aircraft. The AC6800 series feature the Rope Lock System allowing a wheel chock to be temporarily and securely attached to the opposing wheel chock on the opposite side of the aircraft tire. They are ideal for business, commercial, cargo and military aircraft.