Marco Mainspring #501 for Illinois 18s No. 47302 - Steel

Marco Mainspring No. 501 for Illinois 18s movements, Factory No. 47302, 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 in hard to find watch parts and all watch parts are unconditionally guaranteed. mages do a pretty good job of representing the item.