Shimano Ultegra RD-R8150E Di2 Rear Derailleur - 12-Speed, Medium Cage, Includes TL-EW300, Black

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