Can you tell what model this guy is ?
All I have is this photo. Grill looks like maybe battery set? (Going by photo gallery)
It could be a 620B (AC operated)...
...or 623B (battery operated)...
...or 642B (32 volts DC).
Only looking in back will reveal its actual identity. Chances are it is a 620B. In my experience, those sets in order of most to least common are: 620B, 623B, 624B.