Ridgid® clamp screw, for use with model 141 2-1/2 to 4 in pipe and conduit geared threader, model 161 4 to 6 in pipe and conduit geared threader. Ridgid® 39795 Clamp Screw with Clip, for Use with Pipe and Conduit Geared Threader, Pipe and Conduit Geared Threader