Comsco Mainspring #1077 for Elgin 0s & 3/0s Factory No. 2097 - Steel

Comsco Mainspring #1077 for Elgin 0s & 3/0s movements, Factory No. 2097, steel, new in envelope. See images for further details and 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 guaranteed. Images do a pretty good job of representing the item.