2.8cm Vintage 1940s WW2 Propeller Shaped Dark Blue Buttons

These dark blue casein buttons were made in French Canada in the 1940s during World War 2 in the shape of propellers - so the population could show their support for the war effort by sewing them onto the clothes they made.
They are 2.8cm wide.
I have 2 quantities - either 6 or 12 on their original shop cards.