Sandsteel Mainspring - Elgin 1957 for 10/0s & 18/0s movements - Steel

Sandsteel Mainspring for Elgin 10/0s & 18/0s movements, Factory No. 1957, steel, new in envelope. See images for precise mainspring specifications. These were available in a couple of different strengths and the ones I can supply are shown in the drop-down list. I also likely have several of these so the one you get may differ slightly from them 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.