HR Mainspring SA428 for 0s & 3/0s Illinois Pocket Watches #47358 - Alloy

HR Mainspring SA428 for 0s & 3/0s Illinois movements, Factory No. 47358, Alloy, 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.