Marco Mainspring #640 for Howard 10s No. 796 - Steel

Marco Mainspring #640 for Howard 10s movements, Factory No. 796, tongue end, steel, new in envelope. See images for further details and precise mainspring specifications. I likely have several of these so the one you get may differ slight 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.