Zenith

One of those reference 06.0050.400 pieces More info here - Finding the one you really wanted is not easy when in case of this specific example only a few were made. 10? 20 ? No idea but according to some sources it's only 'a few' So again, finding one is...  

Congratulations !

Salve sono Barbara, le scrivo in merito allo zenith el primero in oro 06.0050.400 con lunetta nera in bachelite. Sa indicarmi, cortesemente, un valore approssimativo dell'orologio? Da privato non so a chi rivolgermi. Cordiali saluti. Barbara