Very aggressive vitrified aluminum oxide stones that cut virtually any material except hard stone. They can be used on almost any material including all metals, ceramic tile, porcelain, wood, acrylic, glass, marble and many types of stone. On softer materials like wood they can be used for shaping, carving or texturing. Very cool-running and long-lasting, they are the most aggressive stone made. An economical alternative to diamond burs. 3/32" shanks.