Elgin DuraPower Factory Mainspring for 11/0s & 13/0s No. 6811 - Alloy

Elgin Factory DuraPower Mainspring for 11/0s & 13/0s Series 630 thru 711 plus 721, 724 & 730 movements, Factory No. 6811, alloy, new in envelope. These came in several different strengths and those that I can supply are shown in the variants list. I specialize in hard to find watch parts and all watch parts are guaranteed. Images do a pretty good job of representing the item.