Marco Mainspring #480 for Hamilton 6/0s No. 1721 / 1921 - Steel

Marco Mainspring #480 for Hamilton 6/0s Movements, Models 986 & 988, Factory No. 1721 / 1921, 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 in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.