Marco Mainspring #901 for Rockford 18s Factory No. 644 - Steel

Marco Mainspring #901 for Rockford 18s movements, Factory No. 644, steel, new in envelope. See images for further details. 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.