The Bosch Black Oxide Drill Bit Set have 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. The split-point tips in this oxide set has been engineered for no-skate starts and clean, accurate holes. Bosch's drill bit set 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.