Features3/8 in.
Set includes plastic case.Reverse spiral flutes are designed to bite down to provide maximum gripping power.Hexagonal flats for use with flat wrench, pliers, adjustable wrench, sockets or VISE-GRIP locking pliers.Irwin 585-394002 5-Piece Bolt-Grip Expansion Set square drive for use with hand ratchets, impact wrenches, and air ratchets.