NuVigor Mainspring #310 for Illinois 12s movements Factory No. 47337 - Steel

NuVigor Mainspring #310 for Illinois 12s movements, Factory No. 47337, steel, new in envelope. See images for precise specifications. I likely have several of these so the one you get may differ slightly from the images. I specialize is hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.