Illinois Factory Mainspring for 12s movements Factory No. 47349 - Steel

Illinois Factory Mainspring for 12s movements, Factory No. 47349, steel, new in very frail envelope. One of the beautiful thing about factory mainsprings is they always fit. See images for further details. I likely have several of these so the item may vary in differ slightly from what is shown in the images. See images for further details. 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.