Specifications:

Easy type digital hearing aid
Max Sound Output: 127±4 dB
Max Sound Gain: 52dB ± 5dB
Harmonic Wave Distortion: ≤5%
Low Frequency: 580Hz~~2.8KHz
Middle Frequency: 700Hz~~4.8KHz
High Frequency: 780Hz~~7.8KHz
Wide Frequency: 910Hz~~10.5KHz
Input Noise: ≤30dB
Battery: Lithium Battery
Working Voltage: DC 5V±0.5V
Working Current: ≤8mA
Color: As the picture shows
Item Size: 4 x 3.2 x 1.2cm
Package Size: 15.3 x 9.6 x 3.8cm
Feature: FM Radio, Digital hearing aid, Rechargeable

Package included:

1 x E-8 Hearing aid
8 x Earplug (different sizes)
1 x EU Plug Charger (110-240v.)
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 and plugged, make sure no air leakage.
Keep the ear plug clean
Remove the battery if you don't use it for long time.