Drill for metals HSS, titanium-coated with 5% cobalt. Titanium is a coating material (it has a golden color), which gives the drill higher temperature resistance and less friction. 

Cobalt also has excellent heat resistance and is very hard, but it has the disadvantage of being easily breakable. That's why it is used in a small percentage, 5% in the alloy. 

Such drills are necessary to drill hard metals (Inox, cast iron) but also plain iron-aluminum, bronze, etc. Available in various sizes and diameters.