Elgin DuraPower Factory Mainspring for 20/0s Factory No. 6100 - Alloy

Elgin Factory DuraPower Mainspring for 20/0s movements, Factory No. 6100, in various strengths that you can select from, alloy, new in envelope. See image for precise specifications. 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.