Deore M4120 Shadow 10/11-speed rear derailleur for the dependable shifting performance & durability. Shadow design features a super low profile design & optimized slant angle for super light shifting action Single tension spring prevents contact with the chainstay resulting in a silent ride Direct cable routing prevents snagging from any trail side hazards Wide alloy links & pivot body Fluorine-coated link pin bushings Strong return spring for a positive shifting feel Durable 11T bearing pulleys for low friction Top normal spring uses the spring to select higher gears HG-X11 11-speed & HG-X 10-speed compatible Max low sprocket: 42T (2x 11/2x 10-speed) 41T capacity SGS cage