With aggressive 135 degree tips, these cobalt drills bits?? Not only last longer while drilling?? But also cut faster than standard high speed steel bits. It’s ideal for drilling cast iron, heat-treated steel, stainless steel and other hard materials. Premium Quality, Brand New Solid M35 = H. S + 5% Cobalt 115 PC / Set: 1/16 – 1/2” By 64ths, No. 1 to 60 and A to Z Straight Shank, Fully Ground, in Strong metal box.