Jurgensen Mainspring #664A for Hamilton 8/0s No. 7221 - Steel

Jurgensen Mainspring No. 664A for Hamilton 8/0s movements, Factory No 7221, steel, new in envelope. See images for precise mainspring specifications. 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 a pretty good job of representing the item.