This IRWIN HANSON POWER-GRIP 7-Piece Screw Extractor Set has a 1/4-inch hex shank that fits most drills and quick-change adapters. Each bolt extractor has a reverse spiral flute design that bites down to provide a high amount of gripping power. A high-carbon steel construction gives these screw extractors longer life and increased durability. When faced with a rounded-off, rusted-tight or painted-over bolt, these bolt extractors will help break it free. This set of bolt extractors includes a convenient plastic case for simple storage and transport.