Apex RTB-18 Roof Box-18 Cubicft. Capacity Locking cross bar mounted roof box adds 18 cubic ft. of valuable cargo space on top of cars, SUVs, and crossovers Compatible with both original equipment manufacturer (OEM) and aftermarket crossbars No tool assembly  out of the box and onto your vehicle in 10 minutes Manufactured from high-density polyethylene with a 110 lb. weight capacity to protect your gear in all weather conditions Measures 57" L x 39" W x 19-1/2" H Locking cross bar mounted roof box adds valuable cargo space on top of cars, SUVs, and crossovers Compatible with both original equipment manufacturer (OEM) and aftermarket crossbars No tool assembly  out of the box and onto your vehicle in 10 minutes Manufactured from high-density polyethylene 110 lb. weight capacity