Maximum Voice Frequency Amplification: 13000X. Item Type: Through Wall Microphone Amplifier. 1 x 3.5mm Earphone. Probe Sensitivity: -60dB. EASY TO OPERATE: Press firmly against doors, window and wall and adjust the sound with the knob until you hear a clear sound, able to emit sound from wooden wall, bricks, window and doors, effective noise filtering and faster sound detection.
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