The BAKFlip F1® (Heavy Duty) Tonneau Cover has all of the great good looks and functionality of the BAKFlip FiberMax Model but in a Heavy Duty version Fiberglass Reinforced Polymer (FRP)with advanced impact resistant construction and premium density foam core. Heavy-Duty hardware & components with upgraded latch housing for long-term durability. Evenly distributed weight rating of 400lbs. with a 3 year factory warranty.