The Ebauches Trust (also known as Ebauches S.A.) was from the 1920ies on a roof organization of several ebauche manufacturers, among them the Adolf Michel S.A. (AM) of Grenchen/Switzerland. They made that caliber 72, a form caliber in ladies’ size with a cylinder escapement.
With 6 jewels and a brass balance, it resembles the state of the art of pre WW II: Not ultimately precise, but pretty small and reliable.
Nevertheless, the high time of those tiny cylinder movements did not last very long, since equally small, but much more precise and reliable anchor movements took lover.
Spares might be available for this movement.
Please contact us for availability.