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
– Long cage for double or triple cranksets and 32T max cassette cog
– Includes frame hanger attachment for use with older frame designs