This is for an upgraded alloy Lock Ring that holds the front sprocket spider onto the motor drive pinion on the Bosch Active / Performance Drive Unit.
Substantially tougher than the plastic nuts, although be careful not to cross thread the nut on the drive unit assembly.
For the 2014 / 2015 model Bosch eBike years.
Remember it's reverse thread and only needs to be tightened to 20-25Nm.
We also sell the Bosch Active / Performance Spider Tool to safely remove and replace this nut. (See related products tab).
Just to confirm it's to fit the following motor shape. If you require a Classic+ lock ring, you can find it here.