Our black & gold jobber length drill bits are a general purpose drill bit made from premium hi-molybdenum steel for high strength and have a 135* split point for sinking into hard materials 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. This set goes from 1/16"-1/2" by 64ths and contains 29 pieces. Made in the USA by Norseman Drill & Tool.