CR Mainspring #509 for Howard 12s Factory No. 552 - Steel

Charles Robert Mainspring #509 for Howard 12s movements, Factory No. 552, steel, new in envelope. See images for precise mainspring specifications. I likely have several of these so the one you get may differ slightly from the images. 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.