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:  AG5 Button battery
Max Working Hours with Standard Battery:  50 h
Working Voltage:  D.C. 1.5V
Working Current:  ≤4 mA
Measurement:  4.6×3.8×0.9 cm
Net Weight:  8 g (without Battery)
Special Function Key:  None