Marco Mainspring #552 for Illinois 4s & 6s Factory No. 47354 - Steel

Marco Mainspring No. 552 for Illinois 4s & 6s 1st Model movements, Factory No. 47354, steel, 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.