Milwaukee® nut driver, Impact Duty™ magnetic, 1/4 in drive, 12 mm hex, 2-9/16 in OAL, 0.71 in dia, 0.71 in opening depth, proprietary steel. Milwaukee® 49-66-4612 Impact Duty™ Magnetic Nut Driver, 1/4 in Drive, 12 mm Hex, 10 pk