Descriptions:

Reduction Mode, Tone Adjustable Mild to Moderate
DC5V 1A USB charger
1.Peak OSPL 90 ( dB SPL): 118dB
2.Peak Gain(dB) : 38dB
3.Frequency range (Hz) : 300-4500Hz
4.Distortion : 800Hz : 2.5%, 1600Hz: 3.0%
5.Equivalent Input Noise (dB): 28dB
6. 2 Channel Mode
7.Battery : Rechargeable Li Battery
8.Battery time: 35-40 hours