Illinois Mainspring for 16s Bunn & Sangamo No. 47331 (EXACT) - Alloy

Illinois EXACT Mainspring for 16s Bunn & Sangamo movements, Factory No. 47331, alloy (unbreakable, rustless), new in envelope. See images for precise mainspring specifications and note that this is not for 60hr movements. 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.