These covers for the open holes of the rear engine mounting are made of aluminium and available in silver anodized, black anodized or red. Those 2 covers will be installed in behind the cylinder on the left and right side. You fasten the screw, the o-ring expands and keeps the cover perfect in place.
Shipping contains a set (2 pieces).
When mounting the red or blue aluminium covers, you need to put some oil on the screw head, so that the lacquer is not damaged when screw is tightened (see also installation instruction and installation video).