Grinding wheel, masonry, type 27, depressed center, 4-1/2" x 1/4" x 7/8" 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: 4-1/2" thickness: 1/4" arbor: 7/8" spec: c24s-bf max rpm: 13,300 tool type: right angle grinder