Hamilton Factory Mainspring for 16s 17-21j Factory No. 718041 (317) - Alloy

Hamilton Factory Mainspring for 16s, 17 - 21 Jewel Movements (such as the 956, 974 & 992), Factory No. 718041 / 317, alloy, new in envelope. See images for further details. 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 so I usually have whatever you might need and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.