Attention:
You'd better adjust volume of 40~60dB (as same as usual talk volume or lower than that, gentle and not sharp is advisable) to avoid damage hearing
Take a rest after listening to every half hour, don't use for a long time
Do not use it listening to music when cycling, taking a bus or walking, to avoid accident
Stop use it when you are with dizziness, earache or other unwell symptoms
If there is tinnitus (such as cicadas sound, steam-whistle, metallic sound etc.) or progressive hearing loss, you need to go to the hospital to make a diagnosis and give treatment.