Crown 10/0s Mainspring No. 1324 Made by Waltham - Steel

Crown (N.Y. Standard) 10/0s Mainspring Factory No. 1324 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.