The SQ-500 sensor is the next generation PAR meter from Apogee. However, its very low signal levels prevents its use with most low-cost multimeters. This SQ-500 amplifier board allows you to directly connect and read PAR from any multimeter capable of reading 1mV in either the volt or millivolt range.
Simply plug in the Amplifier to your multi-meter, connect the sensor to the terminal block, turn on the amplifier, and switch your multimeter to the 2V or millivolt range to read PAR on the display. If you are using the 2V range, simply ignore the decimal point.