Check the listing for details. 16.5mm Reduced Shank Drill Bit HSS 6542 Black Oxide 1/2" Straight Shank. Condition: New. Listed at 14.85 USD. High Speed Steel tool - 16.5mm cutting diameter. Good for most general purpose applications, featuring a combination of hardness and toughness for wear resistanceReduced Shank - Expanding the size range capacity of a portable drill chuck. Common flute and overall length for minimal adjustment during tool changesBlack Oxide Finish - Black oxide treatment adds lubricity. Small pockets on the surface of the tool that act to hold coolant near the cutting edgeWide Application - Design for drilling in low and medium tensile strength materials, such aluminum, iron, copper, brass and metalPlease Note: To make clean and precise holes, water is required for lubrication and cooling when drilling metals. Increased use of water lubrication will extend drill bit life.