Panel description: power switch / volume, microphone
socket;audio amplifier button ; whistle button
2. Microphone :
Model No: DZ-518G
Frequency: 300-3 Kilocycle
an integrated device, containing MIC, whistle, audio amplifier, enlarge / diminish sound source. With the most advanced MCU control, the sound from such siren hears consistently pure without any noise. According to the investigation the sound from such siren can be heard within 1km in the ocean.