Marco Mainspring #190 for 10/0s Elgin No. 1957 - Steel

Marco (C&E Marshall) Mainspring #190 for 10/0s Elgin 7j to 15, 4th & 5th model movements, Factory No. 1957, steel, new in envelope. See images for further details. 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.