Shimano dura ace r9100 p power double chainsetthe shimano dura ace r9100 p power double chainset has been totally re engineered to provide you with the optimum balance of low weight and stiffness it features shimanos 4 arm hollow forged aluminium spider which is compatible with various chainring tooth count options in a first for shimano this model is also equipped with an integrated power meter with bluetooth and ant connectivity providing you with in depth power data to help to analyse