Features: 1. Noise reduction circuit: Built-in DSP noise reduction circuit 2. Uniqueness: Imported IC, coupling capacitor 3. Design: The surface relief design to reduce reflection, 2mm pinhole design 4. Silver-plated: Japan imported silver-plated microphone 5. Noise reduction: Dynamic closed-loop noise reduction circuit Description: Monitoring range: 50-10 square meters (adjustable) Working voltage: 6-12VDC, 20MA (MAX) Housing: ABS fireproof material Include: 1 x Audio Pickup Device