1.Max Sound Output: 127dB ± 4dB
2.Max Sound Gain: 48dB ± 5dB
3.Harmonic Wave Distortion: f<1000Hz≤15%,f>1000Hz≤10%
4.Input Noise: ≤32 dB
5.Frequency Range: 450HZ~3500HZ
6.Working Voltage: 1.4V
7.Working Current: ≤1.5mA
8.Battery: AG13 or A675
Special Function Key: N-H Adustement,USA Knowles speaker