Marco Mainspring #516 for Illinois 16s 60hr Factory No. 47309 - Steel

Marco Mainspring #516 for Illinois 16s 60 hr movements, Factory No. 47309, steel, new in frail envelope. See image for further details. 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.