M35 HSS Cobalt - M35 high speed steel makes it last longer than others, Cobalt makes it easy to cut sheet steel, sheet aluminum, copper, plastic, wood and many other things. other sheet metal types with ease. Good Design: Triangular shank fits into power tool chuck securely and eliminates slippage. Twin flute design removes splinters faster and allows particles to escape easily. A necessity for the family, DIYer or professionals - Perfect for home repairs and light jobs such as drilling of holes in plastic, aluminum, copper and many other types of sheet metal, especially for stainless steel plates and steel plates. Slotted tip increases speed. It can automatically deburr the holes while drilling to keep the drill bit clean. You can use water to cool it when it is working and it can be used even longer. Material: high speed steel. Step Drill Sizes: 9 steps (4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm). 20mm.