PFERD Polifan® Coated Abrasive Flap Disc, Threaded, Series: Special Line SGP Z-CURVE, 5 in Disc Dia, 5/8-11 Center Hole Thread Size, 40 Grit, Zirconia Alumina Abrasive, Type PFR/Radial Disc, Fiberglass Backing, 12200 rpm Maximum