[Below: Take a look at the bottom far right of the envelope. You'll see a tiny black word. This is an expertizer's mark, meaning an expert has looked it over and found it genuine. There are many, many fakes of Inselpost stamps.]
[Below: Reverse of envelope.]
[Below: A close-up of the expertizer's mark (I've turned the image rightside up for you to see it better), this is the mark of 'Rungas', a well-known expert in the field. His name is Wolf Rungas, from Munich, and he was an expert in Inselpost expertization.]
