This drill bit set is made of high speed steel. It includes a plastic case, sizes 1/16 in to ½ inch, is designed for use with stainless steel and other hard metal. This 350N series drill bit set has a black and gold finish, and has fractional inch measurements. It is non-coolant through. Plus it has spiral flutes, straight shank with three flats, and neutral cutting direction, and a 135 Degrees drill point.