IRWIN Tools IMPACT Performance Series BOLT GRIP Deep Well Bolt Extractor Set, 3/8-inch Square Drive, Drawer, 14-Piece with 1/4-inch Hex Drive to 3/8-inch Square Socket Adapter (1859153) IMPACT performance series bits are designed specifically for impact drivers and the higher torque they produce. Reverse spiral flutes grip harder as resistance increases for maximum grip power. Deep Well fits over studs to remove even recessed broken fasteners. Constructed of premium high-carbon steel for durability and extended drilling life. Black oxide finish resists corrosion and increases life of extractor. Universal lobular design fits all types of fasteners. Square drive fits impact wrenches, or drills and impact drivers when used with included adapter. Molded ABS resin case holds up to rigors of daily use. Compact, flat design allows for convenient storage in drawers and tool cabinets.