The FSA Pro Road rings are CNC-machined, black anodized 7075-T6 aluminum. Features: Mfg# WA128/Ti-50T CNC Machined AL7075/T6 Laser-etched logos Some are designed to work in specific tooth combinations; parentheses indicate appropriate mating ring Shifting ramps and Stainless steel pins on middle and outer rings S10 is compatible with Shimano, SRAM and Campagnolo Ultra Narrow 10-Speed S9/C10 is compatible with Shimano 9 speed and Campagnolo C10 10-Speed