NuRezista Mainspring #520 for Elgin 0s No. Factory No. 825 - Steel

NuRezista Mainspring #520 for Elgin 0s, Factory No. 825, steel, 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