Milwaukee 4-40 NC Straight Flute Plug Tap & #43 Drill Bit includes a precision-machined Plug Tap designed to create or repair clean, accurate internal threads with ease. This set features long-lasting laser-etched sizing for the clearest markings and a protective Black Oxide coating to resist corrosion. The Plug Tap’s square shank fits all standard tap handles or tap wrenches and is i for through-hole threading. Engineered for durability, these Straight Flute Plug Taps are for cutting threads in common metals such as brass, aluminum, and mild steel. The included drill bit is designed for use with drill drivers to pilot holes accurately. For optimal performance, it is to use cutting fluid with the Plug Taps. Model Number: 49-57-5508