If you want for the fastest, quietest shifting around, look no further.The new SRAM RED Rear Derailleur has been designed to deliver the performance advantage you\'ve come to expect from SRAM. The derailleur is designed with our Exact Actuation technology for precise, efficient shifting.SRAM have paid rapt attention to the finer details, like adding a hollow titanium anchor bolt and even refining tooth geometry of the jockey wheel. The result is that the chain runs through the new RED Rear Derailleur smoother and quieter than ever before.Exact Actuation shifting gives fast, accurate shifts,More clearance with 28t cassettes thanks to longer B-knuckle,New silent shifting with optimized AeroGlide lower pulley, ceramic bearings,New spring-fixed barrel adjuster,New chain pulley cage adds precise chain management,Titanium pinch bolt keeps a low profile while minimizing weight.