Waltham Factory Mainspring for 18s Model 1877 No. 2203 - Steel

Waltham Factory Mainspring, No. 2203 for 18s Model 1877, steel, new in exceedingly frail envelope. See images for further details. I likely have several of these so the one you get may differ slightly from the images but it will be specified strength. I specialize is hard to find watch parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.