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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:   ≤10 mA
Measurement:   7. 0×4. 5×1. 9 cm
Net Weight:   34 g (without Battery)
Special Function Key:   H-N-T Key