The Strong Hand Tools MagSpring Sliding Arm Clamp is ideal for holding round, flat or metal surfaces. Material: Steel, Clamp Pressure (lbs.): 300, Finish Type: Nickel/chrome, Opening (in.): 5 1/2, Throat Depth (in.): 2 1/2, Dimensions L x W x H (in.): 9 x 4 1/2 x 1 1/2