With the fast and accurate Di2 shifting technology, the Shimano 12-speed Ultegra RD-R8150 rear derailleur is extremely versatile thanks to a single cage length option compatible with 11-28, 11-30, and 11-34 cassettes.-Compact design includes an integrated wireless unit, charger, switch-Wider range capacity-Max. low sprocket 34t-LED status indicator-Battery indicator, pairing, adjust mode etc.