Elgin Factory Mainspring for 21/0s No. 5724 - Steel

Elgin Factory Mainspring for 21/0s movements, Factory No. 5724, steel, new in envelope. See images for precise mainspring specifications. These were available in a couple of different strengths and those that I can supply can be found in the drop-down list. Elgin mainsprings are typically coated in very old grease and must be cleaned thoroughly before use. 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