Theses buttons were one of the main reasons I bought this lot. There were 4 cards and only two buttons missing. The back instructions work just like illustrated. Im curious as to the age of these.
They are Pilcher's Detachable Bachelor Buttons. I had never heard of them before, so I did some research. I love the google. They date the buttons by their original maker in the 30s (the ones on the left). Because of the repurposing the ones below are either late 30s or early 40s.