Permotone Unbreakable Mainspring #173 for Bulova 4AD - Alloy

Rezista Permotone mainspring #173 for Bulova caliber 4AD plus perhaps other similar ébauche movements as well, alloy, new in envelope. See images for precise mainspring specifications. I specialize in 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.