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 youve come to expect from SRAM. The derailleur is designed with our Exact Actuation technology for precise, efficient shifting. SRAM has paid 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 provides fast, accurate shifts. New silent shifting with optimized AeroGlide lower pulley and ceramic bearings. Titanium pinch bolt keeps a low profile while minimizing weight. Weighs 145 grams.