microSHIFT M21 Rear Derailleur - 67 Speed 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
- TECH SPECS
| Cage Length | Short |
| Chain Wrap Capacity (teeth) | 39 |
| Color | Black |
| Drivetrain Speeds | 6 |
| Drivetrain Speeds | 7 |
| Largest Cog | 34 |
| Rear Der/Shifter Compatibility | Shimano Mountain |
| Rear Derailleur Mount Type | 10x1 Standard |