Jules Breguet Mainspring for 0s CYMA / Tavannes Pocket Watch - Steel

Jules Breguet Mainspring for CYMA Tavannes 0s Pocket Watch (perhaps caliber 237), steel, new in envelope. See image for precise mainspring specifications. These are Swiss made springs for Lacy & Co in Toronto. 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.