Specification:
Mini BTE Hearing aid
Max Sound Output: 130dB ± 5dB
Max Sound Gain: 48dB ± 5dB
Harmonic Wave Distortion: ≤4%
Frequency Range: 450~3500 hz
Input Noise: ≤30 dB
Battery: AG5 Button battery (Included)
Working Voltage: D.C.1.5V
Working Current: ≤3.5mA
Color: As the picture shows
Item Size: 4.6 x 3.8 x 0.9cm
Package Size: 8.7 x 9.6 x 3.5cm
Net Weight: 8g

Package included:
1 x F-137 Hearing aid
4 x Earplug (different sizes)
2 x AG5 button cell battery
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.