13 Pc. Flexible Combination Ratcheting Wrench Sets, Inch no checkout and machinery Forms a protective and machinery Forms a protective Cuts internal threads in pipes Nominal size of the tap is that of the pipe fitting being tapped Available in National Pipe Taper (NPT) and British Standard Pipe Taper (BSP) Ideal for pipe fittings Tapered at a rate of 3 4" per foot Flexible head Knurled side beam for ratcheting direction indicator 72 teeth ratcheting box end needs as little as 5° to move fasteners versus 30° for standard box end wrenches Surface Drive® on box end provides off corner loading for better grip and reduced fastener rounding