Milwaukee HollowCore Magnetic nut drivers feature a thread-thru design for unlimited depth in threaded rod and long bolt applications. The magnetic universal driver heads fit four times more fasteners including: square, hex, 12 point and spline. Removes rusted and stripped bolts. Designed for maximum durability, the wrench ready hex steel shanks are forged and chrome-plated. Color coded ID markings allow for quick tool identification. Milwaukee nut drivers are designed for the jobsite and include Milwaukee's Limited Lifetime Warranty.