Specifications:
Pocket Hearing aid
Max Sound Output: 129±4 dB
Max Sound Gain: 55dB ± 5dB
Harmonic Wave Distortion: ≤5%
Frequency Range: 350~3500 hz
Input Noise: ≤30 dB
Battery: 1 x AA battery (Not included)
Working Voltage: dc1.5V
Working Current: ≤4mA
Color: As the picture shows
Item Size: 7.0 x 4.2 x 1.8cm
Package Size: 12.0 x 8.5 x 3.5cm
Net Weight: 28g

Package included (One Set):
1 x F-15 Hearing aid
4 x Earplug (different sizes)
1 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 ， make sure no air leakage.
Keep the ear plug clean
Remove the battery if you don't use it for long time.