Wireless Di2 shifting designed for E-MTB and HYPERGLIDE+. The ultra-durable RD-M9260 long-cage, 12-speed rear derailleur pairs best with the CS-M9200 10-51 cassette to deliver features all riders can appreciate. It taps into the same wireless Di2 shifting technology and strengths of the other XTR offerings, while pulling power from the bikes main battery, delivering a stable power supply, and eliminating the need for a back-up battery.