The group develops, manufactures and markets silicon-on-insulator (soi) wafers formed by simox ( separation by implantation of oxygen) technology. simox -soi wafers are manufactured by the group using a specialized oxygen ion implanter, which is developed and manufactured by the group and is integrated with other specialized processes and characterization equipment. simox wafer products accounted for 73% of 2001 revenues; Simox equipment, 21% and other products and services, 6%.