HR Mainspring SA356 for 10s Howard No. 796 - Alloy

HR Mainspring SA356 for 10s Howard Factory No. 796, hook end (basically a Swiss end), alloy, new in envelope. See image for precise characteristics. 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.