Milwaukee 4-40 NC Straight Flute Plug Tap is precision machined to create or repair clean, accurate internal threads with ease. This plug tap features long-lasting laser-etched sizing for clear markings and a protective Black Oxide coating that resists corrosion, ensuring durability in demanding applications. Its square shank fits all standard tap handles or tap wrenches and is specifically designed for through-hole threading. Engineered to cut threads in common metals such as brass, aluminum, and mild steel, this tool delivers reliable performance across various projects. For optimal results, it is to use the Milwaukee Straight Flute Plug Tap with cutting fluid. Model Number: 49-57-5108