Sram red 11 speed rear derailleursram red 11 speed rear derailleur has been designed to deliver the performance advantage you have come to expect from sram the derailleur is equipped with srams exact actuation technology which ensures precise and efficient shifting sram have paid special attention to the finer details like adding a hollow titanium anchor bolt and the use of their aeroglide pulleys the result is that the chain runs through the rear derailleur smoother and quieter than ever