This is a so-called "transitional model" from the 60s, when Omega went from using the name "Seamaster 600" to "Geneve". However, there was a brief period when both names were used on certain watches, making this watch an unusual watch that there aren't many of out there.
 
Brand: Omega
Model: Seamaster 600 Geneve
Material: Steel
Vintage: 1960s
Movement: Mechanical with manual winding
Diameter: 34 mm without crown