The Bosch Black Oxide Drill Bit Set has been designed to satisfy contractors, electricians and other pros who need solid, reliable bits for general-application drilling in wood, plastic and light-gauge metal. A split-point tip on the drill bit set has been engineered for no-skate starts and clean, accurate holes. The black oxide bit provides longer life than standard drill bits, thanks to the tip design and black oxide coating. The three-flat shank design on bits 3/16 in. and larger promotes better gripping and guards against slipping.