These unique clamps provide very quick and secure fastening for repetitive machining operations. They consist of a clamp base along with a customized pin based on the thickness of the part you are clamping. By turning the handle 1/4 turn, the base clamp pulls the pin downward and secures it in position. Four screws and two locating holes allow for secure fastening and precision locating. Mounting bases are also available to provide top side mounting and height adjustment. Recommended workpiece tolerance is +/-.3 mm for the 150 model and +/-.5 mm for the 200 model. The body and cam are made from 4140 alloy steel, heat treated with a black oxide finish. The handle shaft is made from 1045 alloy steel with a black oxide finish. The ball knob is plastic.