NuRezista Mainspring #578 for Waltham 0s Factory No. 2220 - Alloy

NuRezista Mainspring #578 for Waltham 0s, Factory No. 2220, alloy, 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 is hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.