Elgin 5/0s & 6/0s Mainspring Factory No. 2890 Made by Waltham - Steel

Elgin Mainspring for 5/0s & 6/0s movements, Factory No. 2890, marked made by Waltham Watch Company, steel, new in envelope. This is not the first time I've run across a mainspring that Waltham made for a competing maker. Still it's a new mainspring and perfectly suitable for the intended application - and cheap too! I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. Images do an adequate job of representing the item.