Progress Mainspring for Elgin 22s 8 Day Clocks No. 4935 - Steel

Progress Mainspring for Elgin 22s 8 Day clocks, Factory No, 4935, steel, new in envelope.  Found in many different applications, including car clocks, aircraft clocks, travel clocks, ships clocks, and really big pocket watches. These are covered in some very old grease and will need to be cleaned thoroughly before being installed. I specialize is hard to find parts and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.