Hamilton Factory 16s Mainspring Factory No. 318 - Steel

Hamilton Factory Mainspring for 16s 17 Jewel Movements, Factory No. 318, steel, new in envelope. See images for precise specifications including strength. I likely have several of these so the one you get may differ slightly from the images but it will be the strength shown. 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.