Grinding wheel, masonry, type 27, depressed center, 4" x 1/4" x 5/8" arbor c24s-bf. silicon carbide and dual fiberglass reinforced. used primarily on ceramic, masonry, plastic and other non-ferrous materials. quality made to provide fast, safe and dependable service. designed to be used on right angle grinders. wheel size: 4" thickness: 1/4" arbor: 5/8" spec: c24s-bf max rpm: 13,700 tool type: right angle grinder