Hamilton Factory 16s Mainspring Factory No. 317 or 318 - Steel

Hamilton Factory Mainspring for 16s 17 to 21 Jewel Movements, Factory No. 317 or 318, steel, new in possibly frail envelope. See images for precise mainspring specifications. I call this the "use this mainspring if you don't know which one you need" mainspring as it's generic enough for just about any earlier 16s Hamilton grade, of which there were many. 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 an adequate good job of representing the item.