Shimano Saint M820 Shadow+ 10 Speed Rear Derailleur New chain control and silencing technologies in the new RD-M820 are a game changer for gravity riding. In addition to the proven Shadow Plus RD design, a Saint specific, high durometer urethane bump stopper (between the RD and the dropout) was added to reduce impact noise. Now 10-speed, the new RD-M820 features a durable super wide link that serves as the backbone of the DH parallelogram. Ready for track and trail, the mode converter easily adapts between two settings for MTB cassette gear ratios (11-32, 11-34, 11-36) and road (11-23, 11-25, 11-28).