Tiny Tuesday: Stamp/Impression

Many thanks for the smattering of hearts yesterday; you're a generous lot!

The theme for Tiny Tuesday this week is a stamp or impression.  I knew that I had this amongst my late father's possessions and it has always been of interest.  It is a Plumber's work permit issued in 1941 to a Helmut Rasih (?) who was born on 8th April 1924.  My father was taken prisoner by the Germans in October 1943 and remained a prisoner until the end of the war so the owner of the card would have been around 20 years old when my father knew him.  However, I have no idea how or why it came to be in my father's possession or why he retained it all these years.  I note that Helmut's 100th birthday would be coming up in just a few weeks time; I wonder if he had any descendants who would celebrate it?