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

Elgin Factory Mainspring for 21/0s movements, Factory No. 5724, steel, new in envelope. See image for further specifications. I likely have several of these so the one you get may differ slightly from the images. 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 unconditionally guaranteed. Images do a pretty good job of representing the item