Deore M4120 Shadow 10/11-speed rear derailleur for the dependable shifting performance and durability Shadow design features a super low profile design and 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 and 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 and HG-X 10-speed compatible Max low sprocket: 42T (2x11/2x10-speed) 41T capacity SGS cage