Features:   

1.Max sound out put:117+/- 3dB   

2.Sound gain:>= 25dB+/- 5dB 

3.Total harmonic wave distortion:<= 7%   

4.Frequency range:400-4500MHz   

5.Input Noise:<=32dB   

6.Voltage:d.c.1.2V   

7.Current:<=6mA 

8.Main unit, Charing 2 hours for 12 hours use 

9.Charing case 90 mins for hearing aids charing 3~4 times