Hello dear forum members!
I'm new here and living in Sweden and I will shortly describe how I found this place.
To start it all I recently got a old wooden working desk from a passed away relative. When I was cleaning the desk and removed the drawers I found 2 small envelopes with the same size as a credit card.
One of the letter is a Christmas card dated 1926 the second one is undated with a handwritten letter from a older relative that emigrated to the US. In the second letter I found this stamp and my father joked that it probably will be worth a fortune.
So I started my google session.
I came across terms like Scott No. and rotary perforated. 10 or 11 perforated issues. And a lot of other interesting stuff. Also the values are widely spread depending on the stamp.
Here is 2 pictures of the stamp.
The scale is metric and I think it looks to be 11 perforations over 20 mm.
The stamps look to be in very good condition and never hinged, and I think the backside have an even gum surface.


Hope to get some input from you experts.
Best regards
Rob