Kilb-Beck Mainspring #3826 for Elgin 6s No. 824 - Steel

Kilb-Beck Company Mainspring #3826 for 6s Elgin movements, Factory No. 824, steel, new in envelope. See images for precise mainspring specifications. Not very familiar with the Kilb-Beck supply house and would love to find them in a catalog somewhere. I specialize is hard to find watch parts so I usually have whatever you might need and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.