HR Mainspring SA404 for Illinois 18s Factory No. 47303 - Alloy

HR Mainspring SA404 for Illinois 18s movements, Factory No. 47303, alloy new in envelope. See image 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.