CENTURY'S BENCH GRINDING WHEELS ARE MADE FROM VITRIFIED ALUMINUM OXIDE FOR A LONG LIFE AND SUPERIOR MATERIAL REMOVAL. UNIVERSAL NESTED BUSHINGS FIT 1/2"" 5/8"" 3/4"" OR 1"" ARBOR MOUNTS. IDEAL FOR FERROUS METALS. FOR USE WITH STANDARD BENCH TOP GRINDERS. MADE FROM VITRIFIED ALUMINUM OXIDE FOR A LONG LIFE AND SUPERIOR MATERIAL REMOVAL. UNIVERSAL NESTED BUSHINGS FIT 1/2"" 5/8"" 3/4"" OR 1"" ARBOR MOUNTS. IDEAL FOR FERROUS METALS. FOR USE WITH STANDARD BENCH TOP GRINDERS.