About this item M42 Cobalt drill bit set for metal.Using unique process technology, each bit contains about 8% cobalt, which can easily handle common stainless steel materials and various light and medium metals Size - 1/16“ 5/64" 3/32" 7/64" 1/8" 9/64" 5/32" 3/16" 11/64" 13/64" 7/32" 15/64" 1/4" Multi-blade tip-design,increase the pressure on the material when drilling, and it cuts faster and more smoothly than the general 135° drill.;thick web-helix design,fast cuts with smooth chip evacuation Applicable Materials - For Stainless Steel, Cast Iron, Titanium, Light Metals and Aluminum etc Applicable device - CNC machine, precision drilling machine, bench drill, medium and high power electric hand drill