Elgin DuraPower Factory Mainspring for 13/0s grade 711 & similar - Alloy

Elgin Factory DuraPower Mainspring 711 for 13/0s grades 630 - 711 and 719, 721, 724 movements, alloy, new in envelope. There are like a zillion variations of mainsprings for these 13/0s movements, and those that I can supply are shown in the drop-down menu - see for further specifications. I have several of these so the actual one you receive may differ slightly from the images. I specialize is hard to find watch parts and all watch parts are guaranteed. Images do an adequate job of representing the item