Swartchild Black Shield Mainspring for Elgin 0s No. 2097 - Steel

Swartchild Black Shield Mainspring #4368 for Elgin 0s, Factory No. 2097, steel, new in envelope. See images for further details. This is the strength for the 0s not the 3/0s so be sure to check which 2097 you need. I likely have several of these so the one you get may differ slightly from the images (including ones with typos). 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.