The Neiko Tools magnetic nut setter master set comes with 12 hexagonal socket bits in both SAE and metric that locks securely into an impact driver, bit driver or hex socket ratchet to securely grab hexagonal nuts and fasteners for easy installation or loosening / removal. Made with chrome-vanadium steel for increased hardness, high strength, abrasion resistance and long service life. Coated with black phosphate for corrosion and oxidization resistance. This is a full master set that comes with nut driver bits in both metric and SAE. Each nut-setter is clearly engraved on the side with its size. The lobular design head fastener with rounded edges grabs hex nuts by the sides rather than corners to prevent stripping and lengthen service life. Each external hexnut socket has a 1/4" hex socket that's compatible with quick-change chucks and locks firmly in standard chucks.