Bulova Factory Mainspring for caliber 10BA - Steel

Bulova Factory Mainspring for caliber 10BA, steel, new in sealed envelope. See images for further details. The wonderful thing about factory mainsprings is they always fit! That said, the 10BA was based on the ETA 900.  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.