Gossen Trilux light meter.
The Gossen Trilux light meter is used for light measurements. The meter
has 3 ranges and with the including filter, the ranges can be extended.
The meter is very simple to use, just connect the sensor to the correct
sockets and measure the light if necessary, adjust the range and read
there are more Trilux meters with a different unit and value on the
scale. On of them is measuring in the unit Candela and sometimes
referred to as "Candela" light meter however this is still a Trilux