Comsco Mainspring #3940 for Bulova caliber 10AF - Steel

Comsco Mainspring #3940 for Bulova caliber 10 AF caliber movements perhaps other similar ébauche watches, 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 is 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.