WWII Civil Defense Pin with M (for Massachusetts?) in Gilt Sterling

This is a World War II Civil Defense pin with a large red "M" in the background. The M may stand for Massachusetts, or perhaps for a company involved with the group.

Circa World War II.

Approximately 1/2" in height and 1/2" in width.

Gilt sterling silver with enamel.

Vertical pin with C catch.

STERLING GREENDUCK CO. with union marks.

This is from a homefront company collection which we will be listing more of over the next few months. VEX11 LAAEX8/11

8- (Very Fine-Excellent): The pin shows some small spots of light wear and tarnish, mostly on reverse – all enamel is intact.

As with all my artifacts, this piece is guaranteed to be original, as described.