Elgin DuraPower Mainspring for 10s Grade 542 - 546 No. 6001 - Alloy

Elgin Factory DuraPower Mainspring for 10s grade 542 thru 546 movements, Factory No. 6001, alloy, new in envelope. Available in several different strengths which you can select from. I likely have several of these in each strength so the precise one you get may vary from the images shown. I specialize is hard to find watch parts and all watch parts are guaranteed. Images do a pretty good job of representing the item.