The 18 inch Portable Searchlight is more commonly referred to as the Search Light.
The search lights were made during and after WWII, these lights were in general use by the Army, Navy and Air Force whenever they wanted to brightly illuminate an area.

Model: 4-Type MX
Serial Number: 350
Year of Manufacture: 1940-1945
Manufacturer: General Arc Lighting C. Inc. New York
Country of Production: USA

Specifications

Voltage: 40 DC volts
Current: 50 amp lens
Diameter: 490mm
Motor: There are two small motors in the light, the estimation of lighting power would be about 1500 watts light output. One motor drives the top cooling fan ad the other drives the automatic feed for the carbon rods. Light is produced buy the carbon arc process