Clamp is designed to be fastened (via 4 screws not included) to hard surface Pushing clamp handle forward exerts clamp pressure vertically downward Clamp spindle has thick neoprene tip to protect surface of clamped item (replacement tips available, sold separately) Overall length description below is with handle in down (clamped) position Overall Length: 5-1/2" Clamping Force 500 lb