... × 22mmWeight 30gStandard CE FCCDetail Introduction:*Professional wired audio surveillance & monitoring microphone.*Low noise, Low echo ... , clear speech, low price.*Built in digital audio disposal circuit , two step dynamic de- ... line, etc.*Built-in over-loading protection and lightning proof circuit.*Pre-amplifier, directly drive DVR, ... pinhole,hidden,mini,built-in wall Audio Surveillance Microphone