Deore M6100 Shadow plus 12-speed rear derailleur for dependable shifting performance & durability. Shadow plus features a super low profile design & optimized slant angle for super light shifting action. Shadow Plus uses a chain stabilising switch that when on will reduce chain bounce in rough terrain maintaining more stable drive & shifting. Single tension spring prevents contact with the chainstay resulting in a silent ride 13T pulleys & decreased derailleur tension prevent high chain tension in low gears Direct cable routing prevents snagging from any trail side hazards Cold forged wide alloy links & pivot body Fluorine-coated link pin bushings Strong return spring for a positive shifting feel Durable 13T bearing pulleys for low friction Top normal spring uses the spring to select higher gears Max low sprocket: 51T (1x 12-speed) 41T capacity SGS cage