The Shimano Dura-Ace R9150 Di2 is the pinnacle of electronic shifting perfomance. As the flagship level groupset, it utilises the shadow design technology pionneerd by Shimano and offers a sleek appearance and optimised and consistent shifting performance. The low-profile shadow design places it closer inbound to the frame and tucks the derailleur under the cassette. This helps to protect the derailleur in the event of a crash and minimises the general risk of being bumped and banged, allowing it to remain better alinged for smooth, quick and consistently accurate shifting performance. With multiple world tour and grand tour victories, this is the ultimate performance gropuset.