Shimano GRX RD-RX820 12-Speed Rear Derailleur Max 51T

Shimano GRX RD-RX820 12-Speed Rear Derailleur Max 51T With its integrated chain stabilizer; the Shimano GRX RD-RX820 12-Speed Rear Derailleur Max 51T delivers quieter shifting and more secure chain management in rough terrain. The RD-RX822-SGS is compatible with 10-51T; 12-speed SHIMANO MTB cassettes; meaning you?ll never run out of gears even on the steepest jeep road or high mountain singletrack ascent. And the chain tensioner has an ON/OFF switch for easy wheel removal.