Specifications:

BTE Hearing aid
Max Sound Output: 130dB ± 5dB
Sound Gain: ≥50dB
Total Harmonic Wave Distortion: ≤5%
Frequency Range: 300~4000 hz
Input Noise: ≤30 dB
Battery: AG13 button battery
Working Voltage: D.C.1.5 V
Working Current: ≤4mA
Color: As the picture shows
Package Size: 10 x 7.6 x 2.8cm
Net Weight: 7g

Package included:

1 x B-13 Hearing aid
2 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 and plugged, make sure no air leakage.
Keep the ear plug clean
Remove the battery if you don't use it for long time.