Newall Security Mainspring #812 for NY Standard 12s No. 4144 - Steel

Newall Security Mainspring #812 for 12s New York Standard, Factory No. 4144 , steel, new in envelope. See image for precise mainspring specifications. 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.