NuVigor Mainspring #451 for Howard 10s Factory No. 796 - Steel

NuVigor Mainspring #451 for Howard 10s, Factory No. 796, steel, new in possibly very frail 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.