Newall Security #783 Mainspring for Illinois 6/0s Factory No. 47370 - Steel

Newall Security Mainspring #783 for Illinois 6/0s movements, Factory No 47370 (old No. 1095), steel, new in likely frail 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, even the cheap ones. Images do a pretty good job of representing the item.