Abstract: A pair of rails that are movable from a collapsed position to an extended position and function to increase the cargo-carrying volume and stability of a pick-up truck bed. The rails are mounted on rods which are mounted for vertical movement. In the collapsed position, the rods are nested between the outer and inner walls of the truck bed. Similar structure is provided for the tailgate. The rods are provided with vertically spaced apertures so that the cargo may be safely tied down. A wall may be attached to each rail so that the truck bed will be laterally enclosed when the rails are in an extended position. A detachable canopy is provided to span the rails and enclose the top of the bed.