Manufactured from Chrome Molybdenum hardened steel. Easily extract nuts, bolts and screws that are rusted, worn, painted over, or even completely stripped or broken. Internal thread with reverse spiral flutes for superior grip on damaged bolts, providing excellent torque. Includes standard 1/4" and 3/8"Sq drive hex adaptors, allowing the use of hand, air, or power tools. Includes three knock-out pins for easy removal of damaged bolts and nuts once removed. Supplied in durable storage case for easy transportation.