Features and Benefits: Reverse spiral flutes are designed to bite down to provide maximum gripping power; High carbon steel ensures longer life and greater durability; Universal lobular design fits all types of fasteners; When you are faced with a rounded off rusted tight or painted over bolt, bolt extractors will break it free; Set includes plastic case; 3/8" square drive for use with hand ratchets, impact wrenches, and air ratchets; hexagonal flats for use with flat wrench, pliers, adjustable wrench, sockets or Vise-Grip locking pliers. Set includes bolt extractors to remove bolts sizes: 11mm, 14mm, 16mm, 3/8", 7/16", 1/2", 9/16", 5/8" in drive size 3/8".