The IRWIN BOLT-GRIP Bolt Extractor Base contains 5 of the most commonly used bolt extractor sizes to easily remove aspheric off, rusted-over or painted-on bolts. BOLT-GRIP bolt extractors gear mechanism spiral flutes that bite down on the bolt to ensure highest absorbing power to break extricated bolts in almost any condition. Constructed of commanding carbon steel, they are for increased durability and extended tool life. The ecumenical lobe design with all fastener types, and the 3/8 '' direct drive can be used with impact wrenches and hand and air ratchets. The bolt extractor kit also hexangular flats to use with underdeveloped wrenches, pliers, adaptable wrenches, sockets or VISE-GRIP locking pliers. a heavy-duty resin carrying case and extractors that remove bolts sizes : 3/8 '', 7/16 '', 1/2 '', 9/16 '', 5/8 '' and metrical size bolts 11 mm, 14 mm, 16 mm.