Irwin 3/4 in. Round Most Machinable Metals Countersink is crafted from high speed steel featuring a black oxide coating that provides excellent corrosion resistance. Its 5 flute design minimizes vibration, ensuring smoother and more precise drilling. The countersink has a precision-ground 82-degree tip, i for countersinking into most machinable metals. Equipped with a 1/4" round shank, it is compatible with all handheld and stationary drills, making it a versatile tool for various metalworking applications. Model Number: 12413