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

Illinois Factory Mainspring No. 47338 for 12s & 13s "Extra-Thin" Model movements, steel, new envelope. One of the beautiful thing about factory mainsprings is that they always fit. See images for further details. 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 an adequate job of representing the item.