TheShimano Deore XT RD-M8120 12 Speed Shadow+ SGS Rear Derailleurfeatures a super low profile design and optimized slant angle for super light shifting action. ThisShimano Deorederailleur usesa chain stabilising switch that when on will reduce chain bounce in rough terrain maintaining more stable drive and shifting. The single tension spring prevents contact with the chainstay resulting in a silent ride and the rubber bumper on the pulley cage makes for a silent drive. Shimano Deore XT RD-M8120 12 Speed Shadow+ SGS Rear Derailleur Features 13T pulleys and decreased derailleur tension prevent high chain tension in low gears Direct cable routing prevents snagging from any trail side hazards Full carbon fibre outer pulley cage saves weight while alloy inner cage increases rigidity Cold forged wide alloy links and pivot body Four fluorine-coated link pin bushings Strong return spring for a positive shifting feel Shimano Deore XT RD-M8120 12 Speed Shadow+ SGS Rear Derailleur Specifications Specifically designed to work with XTR M9100 12-speed double drivetrains Durable sealed 13T bearing pulleys for low friction Top normal spring uses the spring to select higher gears Max front difference 10T Max low sprocket: 45T (2x 12-speed) 45T capacity SGS cage Average weight: 290g