The 90 centimeter Searchlight was powered by a Lister generator at 90 watts at 120 amperes to create a 2 billion candlepower focused beam of light out to 5 miles (8 kilometers). This model was installed in fixed fortifications, mobile trucks, and on ships for night defense. There were also 120cm and 150cm versions. Right-click and choose "view image" to enlarge.
Many women of the Auxiliary Territorial Service (ATS) were charged with operating these searchlights during air raids. The only all-female Royal Army unit operated 90cm searchlights.