NuRezista Mainspring #521 for Elgin 3/0s No. #2097 - Steel

NuVigor Mainspring No. 521 for Elgin 3/0s, Factory No. 2097, steel, new in envelope. See images 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