Stainless Steel bearing for ultra durability Anti Rust/Corrosion Resistant Anodized 11t for Shimano & Sram 9, 10,11 speed Colour: Blue Weight: 9 grams Dimensions: Width(thickness): 8.5mm, Bolt hole ID: 5mm, Radius: 42mm Shimamo Compatability Shimano XTR, Saint, XT, SLX, Deore, LX, Alivio, DuraAce, Ultegra, Tiagra, 105, Sora or other center bolt designs. Sram Compatability SRAM X0, XX, Force and Rival. These will also fit 2010 onwards SRAM X7 and X9, but they wont fit 2009 or lower X7 and X9.