IRWIN Tools IMPACT Performance Series BOLT GRIP Deep Well Bolt Extractor, 12MM, 3/8-inch Square Drive with 1/4-inch Hex Adapter (1859123). IMPACT performance series bits don't just work with impact drivers. They are designed specifically for them 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. For removing broken, damaged, or rusted nuts, bolts and screws.