Samsonspring Mainspring No. 591 for N. Y. Standard 12s No. 4144 - Steel

Samsonspring No. 591 steel mainspring for NY Standard 12s, Factory No. 4144, new in envelope. See images for precise mainspring specifications. I specialize in 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.