Our Reaper Stiletto Bits are so sharp, they'll cut you if you just look at 'em the wrong way! The varibit-step tip style allows for faster & easier holes in stainless steel, cast iron, sheet metal, plastic, mild steel, spring steel, brass, copper & even plastic! The patented M35 Cobalt alloy incorporates molybdenum & Tungsten. Our shanks are ground with 3 flats from 3/16" - 1/2" for non-slippage in chuck!