Sandsteel Mainspring for Rockford 18s Factory No. 644- Steel

Sandsteel Mainspring for 18s Rockford, Factory No. 644, steel, new in frail envelope. See image 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. Images do a pretty good job of representing the item.