Hamilton 12s Mainspring No. 1228 / 3028 / 718071 (EXACT) - Alloy

Hamilton EXACT Mainspring for 12s 17 Jewel Movements, Factory No's 1228 / 3028 & 718071, alloy, new in envelope. See images for precise mainspring specifications. I likely have quite a few 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.