This site says the United Hatters Cap and Millinery Workers Internacional Union label was in use 1934 through 1983. The United Hatters of North America label has use up to 1934. I believe there was a union merger at that time. https://sammydvintage.com/vintage-style/union-labels/ Here is the FL thread: https://www.thefedoralounge.com/threads/look-for-the-union-label.59329/ There is also some data on the ‘bug’ in the top left corner. It is a mark from a union printer. I have to look back, but I seem to recall the bugs parallel with the top of the label are older than those tangent to the circle. According to the FL thread that change from parallel to slanted happened ~around 1946. Give or take, as always.