Composite picture showing the front and back of an advice of delivery for <a href="https://en.wikipedia.org/wiki/registered_mail" class="extiw" title="en:registered mail">registered mail</a> as used by the <a href="https://en.wikipedia.org/wiki/Austrian_Post_AG" class="extiw" title="en:Austrian Post AG">Austrian Post AG</a> (the federal Austrian postal service).
Österreichische Post AG
<span class="int-own-work">Self-photographed</span>