This hearing amplifiers is a great solution for those who are suffering bad hearing condition or hearing loss. Professiuonal audiological theoretically designed with digital sound noise reduction processing, this ear device actively reduces background noise to provide great hearing experience to the maximum. With handy working mode switch button and volume control button, the user can make accurate adjustments in no time. A wonderful choice for the hard-of-hearing people, the deaf, the elderly, the hearing-impaired, etc. Features - Comfortable wearing: silicone ear buds won't hurt your ears, offering the most comfortable wearing experience.- Sound and voice amplifier: Designed by expert audiologists with professional sound noise reduction process, this ear aid can help the user hear the outside sound more clearly and loudly. Help the user rediscover the pleasure of listening to nature's sounds or talking to others.- Volume control: You can adjust the volume from the minimum volume to the maximum volume as you like.- N-H working mode control: "N" is for normal work mode. "H" can help you reduce low frequency noise, getting clearer sound.- Wide usages. For hard-of-hearing users, the deaf, the elderly, the hearing-impaired, etc.- Preferencial gift box. 4 different sized earplugs can fit most of people's ears. Delicate box is included for easy storage and portable use. Specifications - Color: Black- Material: ABS, silicone- Size: 6.1 x 4.1 x 1.6cm- Type: Pocket Hearing aid- Max Sound Output: 129±4 dB- Max Sound Gain: 58dB ± 5dB- Harmonic Wave Distortion: f<1000Hz≤15%,f1000Hz≤10%- Frequency Range: 450~3500 hz- Input Noise: ≤30 dB- Battery: 1 x AA battery (Without Battery)- Working Voltage: DC 1.5V- Working Current: ≤4mA Note: - Adjust volume to the minimum before wearing, and increase volume gradually to avoid sudden increase in sound.- 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.Packing list: 1 x Hearing aid 4 x Earplug (different sizes) 1 x User manual