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 4X More Fasteners Including: Square, Hex, 12 Point & Spline. Designed For Maximum Durability The Wrench Ready Hex Steel Shanks Are Forged and Chrome Plated. Milwaukee Nut Drivers Are Designed For The Jobsite and Include Milwaukee'S Limited Lifetime Warranty.