Bulova factory mainspring for caliber 10AUC - Steel

Bulova Factory Mainspring for caliber 10AUC automatic (with safety) plus perhaps similar ébauche watches, in envelope, steel. The envelope may not be sealed so as to permit inspection of the mainspring (some are, some aren't). The wonderful thing about factory mainsprings is they always fit! 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.