Shimano dura ace di2 9070 11 speed rear mechdigital integrated intelligence or di2 with programmed automatic motion at the touch of a switch the dura ace di2 rear derailleur is quick smooth and effortless making for unmatched drivetrain efficiency features programmed automatic motion at the touch of a switch makes this derailleur quick smooth and effortless to shift the removal of traditional mechanical cables in favour of electrical wires not only eliminates poor shifting caused by contami