Specifications:_x000D_Pocket Hearing aid_x000D_Max Sound Output: 1295 dB_x000D_Max Sound Gain: 55dB 5dB_x000D_Harmonic Wave Distortion: 5%_x000D_Frequency Range: 450~3500 hz_x000D_Input Noise: 30 dB_x000D_Battery: 1 x AA battery (Without Battery)_x000D_Working Voltage: dc1.5V _x000D_Working Current: 4mA _x000D_Color: As the picture shows_x000D_Item Size: 6.6 x 4.3 x 1.6cm _x000D_Package Size: 8.5 x 12 x 3.3cm _x000D_Package included:_x000D_1 x F-16 Hearing aid_x000D_4 x Earplug (different sizes)_x000D_1 x User manual_x000D_1 x Box_x000D_Note:_x000D_Adjust volume to the minimum before wearing._x000D_Choose an earplug of slightly bigger size to avoid whistler._x000D_Increase volume gradually to avoid sudden increase in sound._x000D_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._x000D_Keep the ear plug clean_x000D_Remove the battery if you don't use it for long time._x000D_