The Shimano CUES RD-U4010 rear derailleur has a compact cage design that is optimized to provide plenty of ground and tire clearance while maintaining smooth shifting performance for small-wheel bikes.Compatible with Shimano 9-Speed (11-36t) and 10-speed (11-39t) LINKGLIDE cassettes onlyShimano Shadow RD technology allows more aggressive riding with its super low profile design that prevents the rear derailleur from hitting the chain stay in rough conditionsWith no cable adjustment barrel you get more clearance for easy tire removal and maintenanceSmooth rolling 11t pulley wheelsCompatible with LINKGLIDE AND HG 11-speed chains