Features Can be applicable to iron, steel, copper, aluminum and other processing Sharp and durable, accurate positioning, cutting edge clear Each bit has a double end and grinding at a standard 60 degree Angle Quick cutting speed, and good chip removal For precise center drilling in metals Specifications: Quantity: 6 PCS Product specification: 1.0mm, 1.5mm,  2mm, 2.5mm, 3mm, 5mm Specific dimensions: as the picture Weight: 60g No. Body diameter Drill tip diameter #1 4mm 1mm #24mm1.5mm #3 5mm 2mm #46mm2.5mm#5 8mm 3mm #6 12mm 5mm Usage:1. Center and spotting drills are traditionally used to make a conical hole for a lathe center in order to make a starting point for a standard twist drill,designed to prevent the twist drill from walking.2. Used for work pieces with require machining between centers or producing center  in components. Package Included: 6 x Center Drill Bits Note: Due to manual measurement, may exist 1-3mm error, please understand, thank you! Package List