Max Sound Output:  130±5 dB
Max Sound Gain:  ≥50 dB
Harmonic Wave Distortion:  ≤5%
Frequency Range:  300~4000 hz
Input Noise:  ≤30 dB
Battery:  5# dry battery
Max Working Hours with Standard Battery:  80 h
Working Voltage:  D.C. 1.5V
Working Current:  ≤4 mA
Measurement:  6.8×4.2×1.8 cm
Net Weight:  26 g (without Battery)
Special Function Key:  N-H Key