Marco Mainspring #301 for 18s Hampden Movements Factory No. 1696 - Steel

Marco Mainspring #301 for 18s Hampden Pocket Watch movements, Factory No. 1696, steel, new in envelope. Could also very well fit in other 18s American watches too (hint, hint). 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.