Shimano RD-R8150 Ultegra Di2 12 Speed Rear Derailleur

With Shimano's fastest, most accurate shifting, the new 12-speed ULTEGRA R8150 rear derailleur is more versatile than ever thanks to a single cage length option that is compatible with 28-34T low sprockets
Features:

Shimano's fastest ever rear shifting, 58% faster than RD-R9150
Compact design includes an integrated wireless unit, charger, and switch
LED status indicator
Battery indicator
Wider range capacity

Specifications:

Rear speeds: 12
RD construction: SHIMANO SHADOW RD
Mount: Direct attachment (conventional), Direct mount
Max. front difference: 16T
Total capacity: 39T
Low sprocket: 30-34T
Top sprocket: 11T
Fluoric coated link bushings: 4
Pulley:
Guide/Tension pulley bearing
Teeth: 11
Sunken type pulley screw
B-axle: Hollow axle
B-axle 2: Hollow axle
Di2 connectivity wired shifting: ✔
Di2 connectivity wireless shifting: ✔
Bluetooth® LE custom |Adjust mode information: ✔
Bluetooth® LE custom |Di2 battery level: ✔
Bluetooth® LE custom |Gear position: ✔
Bluetooth® LE custom |SHIMANO E-BIKE SYSTEMS data items (*3): ✔
Bluetooth® LE custom |Compatible with E-TUBE RIDE: ✔
Bluetooth® LE custom |Compatible with E-TUBE PROJECT: ✔
ANT private |Adjust mode information: ✔
ANT private |Di2 battery level: ✔
ANT private |Gear position: ✔
ANT private |SHIMANO E-BIKE SYSTEMS data items (*3): ✔
Firmware update by E-TUBE PROJECT: ✔
SD50 port (pcs): 0
SD300 port (pcs): 1
SD50 connector (pcs): 0
SD300 connector (pcs): 0
LED for system status: ✔
Charging cable: EW-EC300
Average weight: 262g