GearWrench 388733N 1/8 – 28 BSP Tap The GearWrench 388733N 1/8 – 28 BSP Tap features tapered cutting edges, which give a less aggressive cut than plug taps in small diameters. Manufactured from carbon steel, the GearWrench 388733N 1/8 – 28 BSP Tap has clear laser-etched size markings for easy identification.