Cutting edge machining process allows apex to meet or exceed licensor standards, resulting in tighter tolerances and superior product consistency. Proprietary steel and heat treat process yields greater strength and longer bit life. Better and more consistent fit to fasteners leads to better torque transfer. - Apex Tool Group Power Drive Bit, Length: 1.9375 Inch, Drive Size: 0.25 Inch, Material: Steel, Hex Drive, Tip Type: Socket.