Shimano SLX RD-R7150 12-Speed Rear DerailleurA New Level Of PerformanceElectronic shifting is the next level up from mechanical shifting. These drivetrains provide the crispest and most reliable shifting performance out there. The Shimano SLX RD-R7150 12-Speed Rear Derailleur is a wide 36T-compatible 12-speed Di2 rear derailleur. Receiving the wireless shifting signal from the shift lever, the Shimano 105 rear derailleur completes a shift in the blink of an eye with its high-performance motor and optimized link structure. This is the hub of the Di2 system, with the charging port, indicator LEDs, adjustment switches, and more integrated into a compact package. A low-profile design reduces damage from contact and falls. FeaturesReceiving the wireless shifting signal from the shift lever the Shimano 105 rear derailleur completes a shift in the blink of an eyeHigh-performance motor and optimized link structureLow-profile design reduces damage from contact and falls | Shimano | SLX RD-R7150 12 Speed Rear Derailleur REAR DERAILLEUR, RD-R7150, 105, 12-SPEED, TOP NORMAL, SHAD