TheShimano Zee M640 10 Speed Shdow+ Design Rear Derailleur. Shimano's new ZEE Shadow+ rear derailleur reduces chain slapping and dropping thanks to the Chain Stabiliser system Shimano Zee M640 10 Speed Shdow+ Design Rear Derailleur Features Shimano's new ZEE Shadow+ rear derailleur reduces chain slapping and dropping thanks to the Chain Stabiliser system 10 speed Dyna Sys compatible only Low-profile skid plate design 23-28T
