Description: Made of high speed steel (6542), sturdy and durable. Titanium coated surface, not easy to rust, and long service life. Universal 90-degree 3-edge countersinks compatible with all kinds of drills, drill machines, including vertical drilling machine, and other common milling cutter. 6 sizes, 2 types to meet your different needs: 20.5mm, 16.5mm, 12.4mm, 10.4mm, 8.3mm,6.3mm (countersink top diameter). Great for making countersunk holes, DIY daily use, easy to use and effectively to drill without burr. Suitable for processing metal and some non-metallic materials, such as carbon steel, steel, thin iron plate, insulation board, PVC board, aluminum, soft and hard wood, plastic and so on. Specification: Material: HSS High Speed Steel(6542) Shape: 3 flute Edge: 90 degrees Diameter of top: 20.5mm-0.8'', 16.5mm-0.65'', 12.4mm-0.48'', 10.4mm-0.4'', 8.3mm-0.32'', 6.3mm-0.25'' Diameter of bottom: 10mm-0.39'',10mm-0.39'', 8mm-0.31'', 6mm-0.24'', 6mm-0.24'', 5mm-0.2'' Total Length: 63mm-2.5'', 60mm-2.4'', 56mm-2.2'', 50mm-1.97'', 50mm-1.97'' 45mm-1.77'' Color: Titanize/ Gold/ Silver/, randomly sent, thanks for your understanding. Package Includes: 1 Piece Countersink Drill Bit Note: Please allow 1-3mm error due to manual measurement, pls make sure you do not mind before you bid Due to the difference between different monitors, the picture may not reflect the actual color of the item, pls understand, thank you