. Designed for use with power tools. 1/4" hex shank fits most power tools. 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. Includes: 1/4" drive size: 8mm, 10mm, 11mm, 3/16", 1/4", 5/16", 3/8", 7/16" and 1/2". Packaged in a blow molded case.