Illinois Mainspring for 16s No. 47309 for 60 hr RR watches (EXACT) - Alloy

Illinois EXACT Mainspring for 16s 60 hr RR Movements, Factory No. 47309, Alloy (unbreakable, rustless), 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 in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.