Bolt extractors break free rounded-off, rusted-tight or painted-over boltsReverse spiral flutes are designed to bite down to provide maximum bolt extractor gripping powerEach IRWIN bolt extractor features high-carbon steel construction for long life and durabilityUniversal lobular design fits most types of fasteners3/8-inch square drive for use with hand ratchets, impact wrenches and air ratchets; hexagonal flats for use with flat wrenches, pliers, adjustable wrenches, sockets and VISE-GRIP locking pliersRemoves rounded-off, rusted, over-tightened, and painted-on fasteners easilyReverse spiral flutes bite down and provide maximum gripping powerUniversal lobular design fits all types of fasteners3/8" square drive for use with hand ratchets, impact wrenches and air ratchets; hexagonal flats for use with flat wrenches, pliers, adjustable wrenches, sockets or VISE-GRIP pliersSet includes extractors for removing bolt sizes 11 mm, 14 mm, 16 mm, 3/8", 7/16", 1/2", 9/16", and 5/8" in drive size 3/8"; and plastic case