Industrial Strength Aluminum Construction. Front Cover Remains Flush With Rolling Cover. Low Profile Design. Opens And Closes Easily With The Push Of A Button. Sealed Ball Bearing Roller Design. No Pull Straps; Velcro; Snaps or Springs. Key Lockable In Any Position; Secures Your Valuable Cargo. Unlimited Hauling Flexibility. UV Protected; No Fading. No Maintenance. Great For 5th Wheel Hauling; Improves Mileage By Up To 10 Percent. Limited Lifetime Warranty.