IRWIN Tools 1899923 Impact Performance Series Power Drill Insert Bit Holder Magnet with C-Ring, 12-Inch Length, 5-Piece Built for maximum durability and long life with impact drivers C-ring design has external clip that fits into the retaining ring notch of the insert bit to hold bit securely in place Rare earth magnets, with four times the hold of standard magnets, holds fasteners securely Black oxide finish resists corrosion and increases life of bit 1/4" quick-change shank is designed to work with impact drivers, and reduces slipping in standard drill chucks