Bulova 6AM (Aurore-Villeret 120)

1936-1940 Breguet hairspring Aurore-Villeret 120, Bulova 6AH, FHF 120 and the many variants of these calibres are quite equivalent. Exchangability data are contradictionary in the various movement registers. Therefore here only calibres are listed which are mentioned in several registers as derivatives of these base calibres, or which could be checked for equivalence. The Bulova calibres have design details which are not present in the FHF calibres. So the ebauches came probably from Aurore-Villeret. differences not known between 6AM, 6AN