Marco Mainspring #172 for 4/0s Elgin 1st Model Factory No. 4789 - Steel

Marco Mainspring #172 for 4/0s Elgin 7 to 17J 1st Model movements, Factory No. 4789, steel, new in envelope. See image for further details. 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.