Each of these 115 cobalt drill bits comes organized in a metal indexed storage case for easy transport to your worksite. These cobalt drill bits retain their hardness up to 1000 degrees Fahrenheit making them ideal for drilling cast iron, heat-treated steel, stainless steel and other hard materials. With aggressive 135 degree tips, these cobalt drills bits not only last longer but also cut faster than your standard high speed steel bits! 29 fractional sizes 1/16″ to 1/2″ by 64ths. 26 letter sizes A to Z. 60 numbered wire-gauge sizes 1 to 60. Aggressive 135 degree tips. Split point prevents skating. Listing and template services provided by inkFrog.