J.W. Winco 50.3-HF-10-M3 Retaining Magnet Assembly, GN50.3, Disc Shaped with Threaded Stud, 0.39" Diameter, 0.18" Thickness, M3 x 7 mm Length Threaded Stud, Steel Zinc Plated Housing and Threaded Stud, Hard Ferrite SrFe Magnet (HF Type)