I googled the type on the back of this button to no avail. Any idea as to era? I’m thinking WWII, but I found a WWI military button in the same area of Wisconsin woods just yesterday.
There are a few links like the one below that mention government contracts to different clothing manufacturers.
There is mention of military uniforms, police uniforms etc. & metal buttons. This link is from 1903 & The Lange & Walsh Manufacturing Co. is
highlighted in yellow at the top of the page. There are other links of similar mention. Could very well be from WW1. Good luck in your search. NICE BUTTON !!