NuVigor Mainspring #317 for Illinois 0s movements No. 47358 - Steel

NuVigor Mainspring #317 for Illinois 0s movements, Factory No 47358, steel, new in envelope. See images for precise mainspring 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 marginally adequate job of representing the item.