Shimano Zee RD-M640 10SP Rear Derailleur The Zee derailleur represents the new standard of affordable DH rear derailleurs. Featuring Shimano's innovative Shadow Clutch system that virtually eliminates chain slap and a compact shape designed to protect the derailleur from impacts, the Zee rear derailleur is specifically designed to handle the rigors of extreme downhill and sets a new standard for durability and performance. Features Shimano Shadow Plus RD technology: Super low-profile design with built in chain stabilizer10-speed only Low-profile design Close Ratio Weight: 275g | Shimano | Zee Rd-M640 10Sp Rear Derailleur | Black | Dh, 11-23T/11-28T