The Matco Tools 13-pc 3/8" Bolt Extractor Set, No. MBX13, removes rusted and rounded off nuts and bolts. Left hand spiral flutes grip damaged fasteners, both metric and standard. The set can be used with hand ratchets, wrenches or pneumatic impact wrenches, plus hexagonal flats can be used with a flat wrench or adjustable wrench. The set includes 13 pieces ranging in size from 1/4" to 3/4" as well as 10mm to 19mm.