NuVigor Mainspring #446 for Howard 18s Factory No. 55 - Steel

NuVigor Mainspring #446 for Howard 18s Factory No. 55, steel, new in 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.