These manually retractable bed covers use a sealed ball-bearing roller system for easy one-handed operation. They are key lockable in any position along the rail providing excellent flexibility. Integrated track system adds versatility by allowing the use of t-slot racks from Yakima and Thule providing the ability to mount bike carriers, baskets and other gear above the cover. Tonneau Cover - Embark, Retractable with Channels for Bed Racks, 5.0 Bed