Item Type: CCTV Microphone Material: Aluminium alloy Place of Use and Area: For prison, detention center, detention center, police station, etc. (5 - 50) Signal Transmission Distance: Approx. 1000m/1093.6yd Frequency Response: 20Hz - 20KHz Directional Property: Omnidirectional Connection Mode: 3 Wire system (Red is connected to power positive pole, black is connected to public GND, white is connected to audio positive pole) Transmission Cable: RVVP3 x 1.5mm Power Supply Voltage: DC 9 - 15V Package List 1 x CCTV Microphone 1 x English Manual 1Wide application ranges. Suitable for prison, detention center, detention center, police station, etc. (5 50). 2High sensitivity, low noise, very low power consumption, power supply polarity protection circuit 3Signal transmission distance is approx. 1000m/1093.6yd. Frequency response is 20Hz 20kHz. 4Connection method is 3wire system. Red is connected to power positive pole, black is connected to public GND, white is connected to audio positive pole. 5An electroacoustic instrument that amplifies sound by receiving sound vibrations.