GearWrench 388734N 1/8 – 27 NPT Tap The GearWrench 388734N 1/8 – 27 NPT Tap features tapered cutting edges, which give a less aggressive cut than plug taps in small diameters. Manufactured from carbon steel, the GearWrench 388734N 1/8 – 27 NPT Tap has clear laser-etched size markings for easy identification.