Linhai Landforce 650 mirror cap

I bought a new Linhai ATV, and the mirrors where not tighten properly so they moved around while driving. When I tightened the nuts, I misplaced the caps/plugs that are on the top to keep water away. I decided to make new ones, also with a rubber gasket.
The gasket is of type F-07 which I found in a o-ring kit I had laying around.

Might work on other brand ATVs too, the inner diameter of the hole is aprx 16mm.