Irwin Tools 93723 Single Bit Turned Holder, 1/4" Hex Shank for 5/16" Bit, 3" Designed for insert bits only. Can be used with socket wrench or socket adapter C-ring design has internal clip that fits into retaining ring notch of insert bit to hold bit securely in place Tool-grade construction is suitable for most general-purpose fastener-driving needs Uses a rare earth magnet that is 4 times more powerful than common magnets