Hamilton 12s Mainspring No. 1228 / 3028 (EXACT) - Alloy

Hamilton EXACT Mainspring for 12s Movements, Factory No. 1228 / 3028, 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.