Hampden 3/0s Mainspring No. 9696 Made by Waltham - Steel

Hampden 3/0s Mainspring Factory No. 9696 made by Waltham, steel, new in frail envelope. See images for further details. Waltham didn't mark them except for "Unit Resilient Main Spring." I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do an adequate job of representing the item.