Shimano GRX RD-RX820 12-Speed Rear Derailleur Max 45T

Shimano GRX RD-RX820 12-Speed Rear Derailleur Max 45T With its integrated chain stabilizer and medium cage; the GRX RD-RX820 12-Speed Rear Derailleur Max 45T delivers quieter shifting; better ground clearance and more secure chain management in rough terrain. The RD-RX822-GS is compatible with 10-45T; 12-speed SHIMANO MTB cassettes; and the chain tensioner has an ON/OFF switch for easy wheel removal.