The RetraxONE MX employs a maintenance-free sealed ball-bearing roller system that glides effortlessly along the side rails. A convenient handle eliminates the need for pull straps, Velcro, snaps, or springs. The RetraxONE MX is key-lockable in any position, providing unlimited flexibility while hauling cargo. The cover can support up to 200 pounds evenly distributed for extra cargo capacity in a pinch.