USB Charging Earhook Noise Reduction Hearing Aid Sound Amplifier(Blue)

1. Sound output: 114-122dB Max
2. Sound gain: 30-34dB
3. Total harmonic distortion: 7%
4. Frequency range: 300-3800MHz
5. Input noise: 32dB
6. Voltage: DC 3.7V
7. Current: 2mA
8. Built-in battery: 45mAh
9. Fully charged for about 3 hours
10. Normal work about 45 hours