Nuvinci N171 installation

[rproctor]

After a big delay caused by Covid lockdown I have finally been able to have my N171 hub ,and a braking system , installed.
However I am a bit concerned as my bike technician seems to have a part left over, though he claims it is not part of the hub mechanism.
I have a strong memory of the part being enclosed in the kit.
From my memory it is a rotation limiting cog.

Can anyone tell me where the part should fit or if my memory is faulty.

I have attached photos of the part.

many thanks
Richard

 

[Chalo]

I am a bit concerned as my bike technician seems to have a part left over, though he claims it is not part of the hub mechanism.

I've built up and installed a bunch of those hubs, and even used a couple of them on my own bikes. But I've never seen the component in your pictures.