Swartchild Black Shield Mainspring for Illinois 16s New Model No. 47317 - Steel

Swartchild & Co Black Shield Mainspring No.4379 for Illinois New Model, Factory No. 47317, steel, new in envelope. See images for further details. I likely have several of these so the one you get may differ slightly from the images. I specialize in hard to find watch parts and all watch parts are unconditionally guaranteed. mages do a pretty good job of representing the item.