CR Mainspring for NY Standard Mainspring for 12s No. 4144 - Steel

CR Mainsprings 506 for N.Y. Standard 12s movements, 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. While the plastic wrappers are old and frail, the mainsprings are new and I guarantee them unconditionally. Images do a pretty good job of representing the item.