USR Mainspring for Illinois 6/0s Factory No. 47365 - Steel

USR Mainspring for Illinois 6/0s, Factory No. 47365, steel, new in envelope - some of which are quite frail and torn. These measure at about 2½ x 8 which is about a Dennison half size narrower that a factory mainspring, if not more, so keep that in mind. 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.