Our Mechanics Length drill bits are made from premium high-molybdenum steel for high strength and have a 135* split-point for sinking into hard metals without the drill bit "walking". The black & gold coating provides some lubricity for easier cutting and they are heat treated by nitro-carburizing for added strength. Excellent for drilling hardened steels and stainless steel. Mechanics length drills feature a shank with three machined flats so the bit doesn't slip in the chuck and a shorter overall length than jobber length drill bits. This set goes from 1/16"-1/2" by 32nds and contains 15 pieces. Made in the USA by Norseman Drill & Tool.