Marco Mainspring #584 for Illinois 12/0s Factory No. 47376 - Steel

Marco Mainspring #584 for Illinois 12/0s 1st model Grade 207 movements, Factory No. 47376, steel, new in envelope. See images for further details. 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.