Marco Mainspring #515 for 16s Illinois Factory No. 47321 - Steel

Marco Mainspring #515 for 16s Illinois movements (not 60hr), Factory No. 47321, steel, new in envelope. See images for precise mainspring specifications. I likely have several of these so he 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.