This is a rare Omega Automatic Calatrava watch reference 166.013 from 1963. This watch features a date function. This model first appeared in the 1961 Omega International Collection.

The dial is classic silver tone with steel applied hour indices.

The case of this watch measures 34mm and is all stainless steel. The caseback is the collectible screwback type. The watch retains its original Omega crown. The automatic movement is a caliber 560. 

This is a classic  watch fit for both dress and casual use. 

The watch has been serviced and will come with a one year warranty.