SHIMANO GRX Rear Derailleur (Di2 spec.) RD-RX717-SGS

The GRX RX717 rear derailleur, paired with a 10-51T 12-speed cassette, gives gravel riders the speed, range, and robustness to pursue any gravel challenge. With built-in Automatic Impact Recovery, an impact-deflecting shape, and solid pulleys, this derailleur stands up to hard impacts and still retains its lightning-quick shifting performance. It also features the same battery featured on GRX RX827, XTR M9250, XT M8250, and DEORE M6250 derailleurs, so you can swap batteries between your mountain and gravel bikes