The Bosch 29 pc. Black Oxide Metal Drill Bit Set (BL29) 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. The split-point tip has been engineered for no-skate starts and clean, accurate holes. The 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.