Maximum sound output: 130 +_ 5dB ? ?

Sound gain: more than 50dB ? ?

Total harmonic distortion: less than 5%?

Frequency range: 300Hz ~ 40000Hz ? ?

Input Noise: less than 30 dB ? ?

Operating voltage: 1.5V ? ?

Battery model LR44

Current: less than 4mA

Weight: 74g

Instructions: ?

The wire plug connected to the headset.Then earplug connector (hard) to the headset， earbuds (silica gel) to connect to the headphone connector pedestal ?

The battery installation: Gently open the battery compartment cover， put a AG13/LR44 battery into the battery compartment in the right direction， then close the battery compartment .

Before you use this item ，you have to turn the O-N switch to O(off)，and turn the sound volume to minimum

Then put this item on you ear， keep it tightly

Next， turn this item on(O-N to N)， adjust the volume until you hear clear sound