The XR Series combines the ONE MX with the integrated Trax Rail System that allows for unique and personal customization above your truck bed cover. The RetraxONE XR combines strong durable polycarbonate with a powerful and incredible scratch resistant matte finish paired with a low-profile patented design that streamlines the overall appearance and provides a firm seal. The XR Series optimizes cargo capacity with the cover open or closed providing the ultimate versatility in cargo management. The Trax Rail System will work with most T-slot accessories from Yakima Thule Rhino Rack and many more offering endless possibilities. Pairing the Trax Rail System with accessories offers double the cargo capacity.