microSHIFT M21 Rear Derailleur - 6,7 Speed, Super Short Cage, Black

M21 rear derailleurs are designed to work with 6- and 7-speed Shimano road and mountain shifters. Enjoy the wide variety of bikes you can get going again with M21 rear derailleurs.

• Robust composite and steel construction
• Compatible with Shimano 6- and 7-speed mountain and road systems