Large opal photo lamp

This was found under the floor in a house, one room of which had been used as a home photo studio in the past.

Age is unknown, but most likely from the 1960s.

Size Comparison

Large photo lamp next to a standard 60W bulb This large lamp is shown next to a standard size 60W type. Although the cap is the same (BC / bayonet), the lamp itself is more than twice the size.

End cap markings

Large photo lamp showing BC cap Large photo lamp showing BC cap The cap is marked 200-210-150.

The actual voltage and wattage of this lamp is not clear. It does not work.

Possibly 200-210V, 150W?