Marco Mainspring #409 for Hamilton 16s Model 960 to 973, No. 317 - Steel

Marco Mainspring No. 409 for Hamilton 16s Model 960, 961, 964, 965, 968, 969, 970, 971, 972, 973 movements, Factory No. 317, steel, 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 is hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.