SRAM Force WiFli Rear Derailleur - 10 Speed Medium Cage Black/SilverSRAM Force WiFli Rear Derailleur 10 Speed Medium Cage Black Silver. Competition grade rear derailleur with carbon and magnesium to keep weight low. Designed for easy to set up and adjustment. Carbon & aluminum pulley cage magnesium inner parallelogram link Must be used with SRAM Double Tap shifter Exact Actuation Ratio delivers 3mm motion per shift across the entire cassette Works with standard or compact 10 speed road cranks TECH SPECS Rear