Ridgid Model 141 Manual Receding Geared Threader Pipe Dies High-Speed (HS) RH. (NPSM) National Pipe Straight Mechanical - Use (NPT) Dies and Rotate Threader Guide Post 180. (BSPP) British Standard Pipe Parallel - Use (BSPT) Dies and Rotate Threader Guide Post 180 requires BSPT threader. Options available for cast iron, PVC, and stainless steel. Pack of 1