These were developed in the late 1930s, with a 60 centimetres (24 in) diameter parabolic glass reflector and was powered by an 8 kilowatt generator. The lamp output was rated at 135 million candelas, and it had a detection range of about 5 kilometres for targets travelling at an altitude of 1,500 metres. With the beam dispersed, this reduced to about 3.2 kilometres. It required a crew of three and could be transported using a single axle Special trailer 51. One of the crew operated the searchlight, another operated the generator, and the third was the section commander.
