Elgin 0s Mainspring No. 825 Made by Waltham - Steel

Elgin 0s Mainspring Factory No. 825 made by Waltham, steel, new in very frail envelope. See images for further details. Waltham didn't mark them except for "Unit Resilient Main Spring." 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 an adequate job of representing the item.