Elgin Factory Mainspring for 21/0s No. 5327 (300-C) - Steel

Elgin Factory Mainspring for 21/0s movements, Factory No. 5327 (300-C), steel, new in envelope. See image for further specifications. Elgin mainsprings are typically coated in very old grease and must be cleaned before use. I specialize in hard to find watch parts and all watch parts are guaranteed. Images do a pretty good job of representing the item