The #4 Ascender is intended for litter raising and load hauling where extra strength and light weight is required. It is not intended to be used as a self belay by solo climbers. Features an aluminum shell, forged aluminum cam and is spring loaded, but can be converted to a free running cam by removing the connecting pin from the cam. Use with 5/8″ (16 mm) and 3/4″ (19 mm) rope only. Made in the U.S.A.