Sandsteel Mainspring for 16s N.Y. Standard No. 1321 - Steel

Sandsteel Mainspring for 16s N.Y. Standard "Crown" and other movements, Factory No. 1321, steel, new in envelope. See images for precise mainspring specifications. 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.