Why choose us? Our products are of better quality and more in line with customer needs, and have been praised by thousands of buyers Hearing Aids For Deaf Elderly Invisible Hearing Device Ear Hearing Amplifier Adjustable Tone Sound Amplifier audifonos para sordera headphones Feature 1.Multi channel analysis: 8channelsand12frequencybands. 2.Easy to Operate, Easy to Use for elderly. 3.Invisible design: you dont have to worry about the awkwardne of wearing a hearing aid. 4. Intelligent Noise Reduction System TechnicalSpecification: 1. MAXOSPL90dBSPL111 2. HFAOSPL90(dBSPL107 3. PeakGaindB39 4. HFAFOGdB34 5. FrequencyRange 6. F1200HzF27200Hz 7. THDat500Hz2.0% 8. THDat800Hz1.0% 9. THDat1600Hz0.4% 10. Eq.InputNoiseLeveldB23.4 11. BatteryCurrentDrain(mA)1.59 12.Hearing Aid Batteries:A10 10A ZA10 10 S10 Zinc Air 10/A10 8channelsand12frequencybands,advanceddigitalchipdesign,invisibledesign,amplifierstability, intelligentnoisereduction,longbatterylife. Prompt: ThereareWhistleasyouputthebatteryintothehearingaid. Pleasedonotworry.becausetheairpresurewillmakeWhistle. 1.Pleaseadjustlowervolume. 2.Choosethesuitableearplug 3.Makesureifyouputtheearplugtightly,soundleakwillmaketheWhistle.