It would hang in a Window or on a Wall, it shows the Son, Brother or Father that Served During the war.
Later I will post a Canadian One
Are they rare? It sounds like they would be a ton of them out there but I am wondering why I am not able to find another picture of one. Do they have a specific name because I googled "For World Liberty" poster and certificate and got none of these.
I agree...A "Son in the Service" window-sign produced post-WWI (1919) as indicated...It appears to be for an Artilleryman as it incorporates the "Flaming Bomb" insignia. Indeed mass-produced, but we see more variations in WWI-Era posters when compared to the more familiar Blue/Gold Star Mothers signs of WWII...Not necessarily rare, but look great framed and displayed as a back-drop for your display...around $25.00 (maximum) in my opinion...
There are many patterns of these, I have 2 Canadian ones, very different in looks, but both for the same thing. Made different companies made these.
Canadian ones sell for about $100, but it depends on the unit ect.