Specifications:Mini ITE Hearing aidMax Sound Output: ��120 dBMax Sound Gain: ��30 dBHarmonic Wave Distortion: f<1000Hz��10%，f>1000Hz��4%Frequency Range: 250~3800 HzInput Noise: ��50 dBBattery: AG3 Button battery (Included) Working Voltage: dc1.5V Working Current: ��4mA Package included:1 x K-86 Hearing aid 3 x Earplug (different sizes)2 x AG3 Button battery1 x User manual Note:Adjust volume to the minimum before wearing.Choose an earplug of slightly bigger size to avoid whistler.Increase volume gradually to avoid sudden increase in sound.If you hear a howling， check the ear (silica gel) is appropriate and whether the size of plug is tight， the appropriate choice of earplugs and plugged， make sure no air leakage. Keep the ear plug cleanRemove the battery if you don't use it for long time.