Hello Big Rig truck drivers. For use with tires up to 44″ in diameter. High-tensile strength aluminum construction. Large rear-opening hand grip for easy transport and placement. “Easy-Grip” carrying handle protects fingers and makes transportation a breeze. Easily folds up and tucks away under the running board, providing increased safety in less space. Each choc requires an area of only 6″ H x 10-1/2″ W x 20-3/8″ D for storage. NFPA/SAEJ348 compliant and third-party tested.