Progress Mainspring for Waltham 00s Factory No. 2221 - Steel

Progress Mainspring for Waltham 00s (2/0s) Movements, Factory No. 2221, steel, new in envelope. See images for further details. I likely have several of theses 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.