Thunderbolt® drill bits are designed for use with cordless and other portable drills. The bits are engineered with a thicker web and unique flute form which allows for quicker penetration and improved drilling times. With increased strength built into the web, the Thunderbolt® bit can perform many operations where conventional bits break. The open flute form ejects chips more efficiently when drilling deep holes which helps prevent lock-ups at breakthrough. Black and bronze high speed steel provides heat resistance, durability and increases bit life.