The Shimano Dura-Ace Di2 9250 Rear Derailleur is the heart of your favorite 12-speed electronic groupset. This derailleur leads to faster shifting than ever across their widest available gear range at 58 percent faster than the previous iteration. It integrates your wireless connectivity with the system charging port and leads to incredibly accurate shifts. An LED indicator light alerts you of battery, pairing, and adjust mode. The range capacity is also wider than ever with a 34t max low sprocket on a single cage length. The Shimano Dura-Ace Di2 9250 Rear Derailleur is an innovative component for world class shifting.