Shimano 105 RD-R7150 12-Speed Rear Derailleur A New Level Of Performance Electronic shifting is the next level up from mechanical shifting. These drivetrains provide the crispest and most reliable shifting performance out there. The Shimano 105 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. Features Receiving the wireless shifting signal from the shift lever the Shimano 105 rear derailleur completes a shift in the blink of an eye High-performance motor and optimized link structure Low-profile design reduces damage from contact and falls | Shimano | 105 Rd-R7150 12 Speed Rear Derailleur Rear Derailleur, Rd-R7150, 105, 12-Speed, Top Normal, Shad