National Unbreakable Mainspring for Hamilton 22/0s #6221 / 718601 - Alloy

National Mainspring for 22/0s Hamilton, Factory No. 6221 / 718601, alloy, new in envelope. See images for additional information. 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 so I usually have whatever you might need and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.