The Shimano Deore M5100 Rear Derailleur 11-Speed Shadow+ is great for dependable shifting performance and durability. The shadow plus features a super low profile design and optimized slant angle for super light shifting action and uses a chain stabilising switch that when on will reduce chain bounce in rough terrain maintaining more stable drive and shifting.Shimano Deore M5100 Rear Derailleur 11-Speed Shadow+ Highlights-Single tension spring prevents contact with the chainstay resulting in a silent ride13T pulleys and decreased derailleur tension prevent high chain tension in low gearsDirect cable routing prevents snagging from any trail side hazardsWide alloy links and pivot bodyFluorine-coated link pin bushingsStrong return spring for a positive shifting feelDurable 13T bearing pulleys for low frictionTop normal spring uses the spring to select higher gearsMax low sprocket: 51T (1x 11-speed)40T capacity SGS cage