This drill set has a sharp edge that does not cause any problems with hard cutting materials such as stainless steel, hard steel and other hard cutting. Set Contents: 0.06 inch (1.5 mm) 2.5 3.0 3.2 3.5 4.0 4.5 4.8 5.0 5.5 6.0 6.5 Cobalt High Speed Steel (HSCO4 M2 )