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