Swartchild Black Shield Mainspring For Hamilton 6/0s Factory No. 2521 - Steel

Swartchild Black Shield Mainspring No. 440788 for Hamilton 6/0s Factory No. 2521, 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 is hard to find watch parts so I usually have whatever you might need and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.