Shimano Ultegra Di2 RD-R8150 12 Speed Rear Derailleur (Black) Return-Yes Disc Brake

Disc Brake

stainless steel body plates help reduce flex

Extra-long rail

where the smallest sprocket has 10t

M: Bontrager Comp Lowriser

Shimano Ultegra Di2 RD-R8150 12 Speed Rear Derailleur (Black) Return-Yes Disc BrakeThe Shimano Ultegra Di2 RD R8150 rear derailleur speeds up the shifting process by 58 % compared to the previous generation Dura Ace model RD R9150. The rear derailleur with an uniform cage length and an increased gear ratio of 34 teeth is thus not only faster than ever before, but also guarantees highly precise functionality under all conditions. Features Integrated with Shimano's latest Di2 platform, offering precise and lightning fast electronic