Here’s the technical specification as per the manufacturer:
Frequency Range: 800 MHz to 2700 MHz (2.7 GHz)
Measurement Range: Power flux density (PFD) 0.1 to 1999 µW/m²
Basic accuracy including linearity tolerance : +/- 6dB
Display: Zero offset and rollover +/- 9 digits
Microwave Sensor: Logarithmic periodic antenna
Audio: Identification of pulsed radiation sources by means of an acoustic signal proportional to the modulated frequency
Power supply: 9 Volt alkaline manganese battery (included). Average operation time 6 to 7 hours.
Low-Battery indication, auto-power-off
Signal Rating: Display of peak and average value (switchable)