Thunderbolt web provides longer life and faster driller timesCorrosion - black oxide coating provides lubricity and resists corrosion of the bitReduced slipping - 3-flat Secure-Grip™ shank holds the bit firmly in the drill chuckFast, accurate drilling - 135-Degree split point tip starts on contact to prevent walkingVersatile - extended length for hard to reach areas, with reduced shank diameter for use in 3/8 in. chucks