Swartchild Black Shield Mainspring for Illinois 12s Factory No. 47344 - Steel

Swartchild & Co Black Shield Mainspring No. 4381 for Illinois 12s New Model movements, Factory No. 47344, steel, new in dirty envelope. See images for further details. I likely have several of these so the one you get may differ slightly from the images. I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.