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.