Shimano dura ace 9000 outer chainring blacksilver 50 tooth
The dura ace 9000 outer chainring from shimano is a genuine shimano replacement part it uses a 4 arm design which is not only stiff but also lightweight and uses the same spider for both inner and outer chainrings it is 11 speed compatible and uses hollowtech and hollowglide technologies available in blacksilver outer chainring only