Swartchild Black Shield Mainspring #4388 for Rockford 6s No. 544 - Steel

Swartchild & Co Black Shield Mainspring No.4388 for Rockford 6s New Model pocket watch movements, Factory No. 544, steel, new in envelope. See images for precise mainspring specifications. 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. Images do a pretty good job of representing the item.