SportRack Horizon Roof Cargo Box; Rear Opening; 18 Cubic Ft. Capacity; 63Lx38Wx19H; For Use w/Original Equipment/Aftermarket Crossbars; The Horizon Cargo Box gives you additional cargo carrying capacity at a great value. It mounts quickly and conveniently on the roof, and compacts for easy storage. The Horizon Cargo Box protected by its durable, weather resistant construction. The Horizon Cargo Box mounts directly to most original equipment and aftermarket crossbars.