1.Size - Cutting edge diameter: 8.5mm / 11/32'; round shank diameter: 8.5mm / 11/32'; cutting edge length: 81mm / 3.19'; overall length: 122mm / 4.8'; split point: 135 degree (Fast cutting point penetrates quickly with less pressure and prevents walking on metal surfaces.) 2.Material - 4341 high-speed steel contains high content of carbon and alloy elements, providing excellent cutting performance, high heat resistance, high hardness, wear resistance and durability. Suitable for applications requiring precise and efficient processing. 3.Features - Black nitride coating can improve hardness, increase wear resistance and prolong its life. The nitride coating also reduces friction in the drilling process, resulting in smoother and faster drilling performance. 4.Applications - Drill clean and accurate holes in stainless steel, cast iron, carbon steel, aluminum alloy, copper, and brass, wood and plastic. Large spiral grooves facilitate the export of metal chips, saving time an effort. NOT suitable for tiles, concrete, walls, stones.