Triple fiberglass reinforcement provides added strength for aggressive stock removal|Type 27 grinding wheels are designed with fiberglass cut back from the edge to provide instant aggressive grinding right out of the box|Type 28 grinding wheels with a concave, or saucer, shape are designed for increased aggression at lower working angles and increased access to the work piece|Choose from aluminum oxide (AO), ceramic alumina, and zirconia alumina abrasives materials|Grinding wheel and cut/grind combo wheel types available