Comsco Mainspring #1155 for Illinois 12s Factory No. 47337 - Steel

Comsco Mainspring #1155 for Illinois 12s movements, Factory No. 47337, 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. Images do a pretty good job of representing the item.