Bulova mainspring 9AB 10AU 10AUC + MST 410 411

1 mainspring Bulova 9AB automatic / Ressort de barillet / Zugfeder

New old stock / neuf de stock

Same mainspring for following calibers :

Bulova 9AB 10AU 10AUC + MST 410 411 

For automatic movement only (mainspring with attached bridle)