Hampden Factory Mainspring 8/0s No. No. 15696 - Steel

Hampden Factory Mainspring for 8/0s movements, Factory No. 15696, steel, in original envelope that's in remarkable condition. See images for precise mainspring specifications and further details. I goes without saying that Hampden was out of business (and on the way to Russia) by 1930 so this mainspring is probably close to 95 years old.  I specialize is hard to find watch parts and all watch parts are guaranteed. Images do a pretty good job of representing the item.