EKAR 13 speed derailleur is custom designed to work specifically in conjuction with the EKAR drivetrain One specific function allows it to be fine tuned for optimal performanceParallelogram 2D trajectory designed to work flawlessly with larger cog jumps and EKAR cassettesRedesigned mechanical clutch system works to absorb chain shock on any terrainDifferentiated pulleys offer better control and retention of the chainEKAR13sp44LongBLKUPC/EAN/GTIN: 8053340455421