Technical Parameters: Sensitivity: 52dB Impedance: 2.2 KΩ-30% Flat rate: 20 ~ 16.000HZ Operating voltage: 10V (TVU) Reference operating voltage: 4.5V Current consumption: 0.5mA (max) Sensitivity attenuation: ≤-3dB at 2-1.5v Packing: 10Pcs