Sandsteel Mainspring for Illinois 3/0s No. 47359 - Steel

Sandsteel Mainspring for Illinois 3/0s movements, Factory No. 47359, steel, new in envelope. See images for precise mainspring specifications and 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.