Pipe Taper Tap Set, 6 Piece, High Carbon Steel, 1/8" to 1", in Wooden Case Plug, Taper and Bottom Taps. Best suited for maintenance and repair work. 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.