Warning not compatible with pre 2015 groupsetsits the heart and soul of the record 11s drivetrain the record rear derailleur has always evoked competitions and wins and still today represents for professional racers the certainty of fast and extremely precise shifting even under load but you dont have to be a pro to take advantage of the performance features of the record 11 speed the fun is for allthe new shape of the external components allows the rear derailleur to move efficient