The cause of howling/noise: To make a small size hearing aid, the internal amplifier and the microphone are close to each other. The sound is continuously received and extended, so it has a certain possibility of producing howling after power-on.
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1-10pcs 803035 Battery 800mAh 3.7V Li-polymer Lithium Rechargeable Batteries for Smart Bracelet Bluetooth Headset Speaker GPS
Aliexpress UK
Why is there a whistling during the wearing process?. We give 3 different sizes of earplugs to reduce howling and noise. Suitable for mild to moderate severe hearing loss (Reference hearing loss map).
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502030 battery 3.7V 250mAh 502030 polymer lithium ion rechargeable battery for toys, LED lights, Bluetooth earphone
Aliexpress UK
1 Pair Mini Invisible Hearing Aids In-Ear Digital Enhancer Voice Sound Amplifier 300mAh with Digital Display Charging Case. 【SMALL AND CONVENIENT DEVICE】It has a miniature appearance comparable to headphones, so you won't attract any unpleasant glances when using it.
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3.7V Lithium Polymer Battery lipo cellS 1800mAh For Wireless keyboard K3 LED lights Bluetooth Car camera recorder 3032130
Aliexpress UK
Rechargeable Hearing Aids for Seniors with Noise Cancelling,Hearing Loss Hearing Amplifiers,Digital Hearing Aid,Sound amplifier with Volume Control Features: 1. Rechargeable BTE Sound Amplifier (Left and Right): A rechargeable BTE hearing amplifier specially designed for the elderly and people with hearing loss. Perfect gift for seniors 2. Easy to Place and Discreet Design: It is lightweight and comes with comfortable ear hooks. The hearing aid's tube adapts to the contours of your ear for ease and comfort. It curves so neatly behind your ears that no one will notice you're wearing it. .
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3.7V 18650 lithium battery 1200-3500mah for Bluetooth speaker singing machine flashlight K5 disinfection gun hair clipper
Aliexpress UK
Rechargeable Hearing Aids for Seniors with Noise Cancelling,Hearing Loss Hearing Amplifiers,Digital Hearing Aid,Sound amplifier with Volume Control Features: 1. Rechargeable BTE Sound Amplifier (Left and Right): A rechargeable BTE hearing amplifier specially designed for the elderly and people with hearing loss. Perfect gift for seniors 2. Easy to Place and Discreet Design: It is lightweight and comes with comfortable ear hooks. The hearing aid's tube adapts to the contours of your ear for ease and comfort. It curves so neatly behind your ears that no one will notice you're wearing it. 3. Long-lasting Battery: Charging time is 2.5 hours, battery life is up to 40 hours. .
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1-10PCS Batteries 3.7V Li-Polymer 10Ah 11*55*100mm Li battery For Tablet Power Bank Bluetooth Speakers DVD 1155100
Aliexpress UK
Features:-It adopts a mini size design and a Bluetooth earphone appearance, which is different from the old hearing aid and is invisible and burden-free to wear.-Built-in the latest chip to achieve the best hearing aid function and help the hearing-impaired people hear sounds normally.-With multi-level volume adjustment, you can adjust the required hearing aid volume according to your needs. After wearing and turning on the device, double-click/triple-click to adjust the volume.-It automatically enters hearing aid mode when turned on, which is easy to use and more suitable for elderly users.-It can also be used as Bluetooth earphones. After turning on, you can switch to Bluetooth mode by long pressing it. Please note that the Bluetooth headset mode only.
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3.7V 800 mAh 3 Wires Thermistor Polymer Li Lithium Li-Po Battery 603040 For GPS Car Camera PDA MID ipod Bluetooth Device LED
Aliexpress UK
Rechargeable Hearing Aids for Seniors-Digital Hearing Amplifiers with Noise Cancelling Crystal Clear Sound Quality Voice Recognition&Tinnitus Relief Wireless Charging Case Features: 1. A true OTC Hearing Aid,Not Just Amplification: hearing aids are designed with an advanced digital chip that significantly reduces background noise while enhancing speech intelligibility for seniors and adults,ensuring effective communication and easy access to information. .
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3.7V 1200mAh 4.44Wh Li-Polymer Thermistor 3-Wires Rechageable Li Lipo Battery 503759 For GPS Bluetooth Speaker LED Light DashCam
Aliexpress UK
MiNi Digital Invisible Hearing Aids CIC Small Sound Voice Amplifier Enhancer US. This hearing amplifier is almost invisible when you are wearing it, it features highly advanced amplification technology, it is easy to hide and comfortable to wear.
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3.7V 400 mAh 1.48Wh Polymer Li Lithium Battery Cell 602035 Li-ion For MP4 Bluetooth Speaker LED Light Driving Recorder DashCam
Aliexpress UK