Crescent Mainspring for 12s - 13s Illinois Factory No. 47338 - Steel

Crescent Mainspring for 12s - 13s Illinois Thin Model Motor Barrel, Factory No. 47338 (really old #1845), steel, new in envelope. 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. See image for precise characteristics. Images do a pretty good job of representing the item.