The A.R.E. HD Series Truck Cap offers an interior aluminum support framework, which reinforces the fiberglass cap construction by routing all roof rack and toolbox weight to the bedrail of the pickup truck. According to the company, the design nearly triples load capacities, allowing a 550-lb capacity on the roof rack and 200 lbs in each toolbox. Optional heavy duty side doors provide access to two steel toolbox inserts. The side and rear doors can be upgraded with aluminum inserts with foldable T-handles. The HD Series comes with a limited lifetime warranty on materials and workmanship.