I forgive only 4 stars for the adapter. The build quality is ok, if not perfect. For me, an external connector side (round, flat metal) has a notch. Probably a smaller Matarialfehler. I would say optical B-Ware. Well, it works, and met after 3 weeks still its purpose. From the dimensions very precisely, since there is nothing to complain about!
The Beizeichung is wrong, this article has nothing to do with an F connector.