Designed for use on horizontal machining centers, these clamping screws attach to hook-type clamping modules to provide safe and easy loading and unloading of heavy workpieces or fixture plates. These clamping screws enable you to hang the workpiece easily before clamping. Use the CP166 clamping screws when locating the workpiece is not necessary (and use CP165 screws when locating is necessary). The bushing made from 1045 steel, with a black oxide finish. The clamping screw is made from 4135 steel, quenched and tempered, with a black oxide finish. The O-ring is made from nitrile rubber.