Hampden Factory Mainspring 12s No. No. 7696 - Steel

Hampden Factory Mainspring for 12s movements, Factory No. 7696, steel, new in a well handled envelope. See images for further details. The envelopes original measurements have been adjusted by someone before me (probably by about 50 years) to the actual specifications. I specialize is hard to find watch parts and all watch parts are guaranteed. Images do a pretty good job of representing the item.