hilmor 1839054 3" Quick Change Magnetic Nut Driver, 1/4" + 5/16" Quickly switch between 1/4" and 5/16", the two most common sizes A magnetic tip on both ends keeps fasteners firmly in place A color-coded insert on the bands and bottom makes size identification simple A hollowed shaft allows for use on long bolts Designed to last with a durable chrome-vanadium steel construction