Marco Mainspring #484 for Hamilton 12/0s Model 401 No. 4128 - Steel

Marco Mainspring No. 484 for Hamilton 12/0s Model 401 19j movements and likely others as well, Factory No. 4128, 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.