Deep well design fits over exposed studs and reaches recessed fasteners. Reduced profile head enables use in confined spaces. 3/8 in. 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. When you are faced with a rounded-off, rusted-tight or painted-over bolt, bolt extractors will break it free. Reverse spiral flutes are designed to bite down to provide maximum gripping power. Universal lobular design fits all types of fasteners. Set includes plastic case.