Tips for buyers: The cause of howling/noise: The internal amplifier and the microphone are close to each other of the hearing aid, and the sound is continuously received and expanded, so it has a certain possibility of produce howling after power-on. At present, small hearing aids and high-power hearing aids on the market can hardly avoid howling, and only full-digital hearing aids can avoid howling. Ways to avoid howling/noise: 1. When the power is high (the amplified sound is large), howling is more likely to occur. Therefore, gradually increasing the volume from low can effectively avoid howling. 2. When the ear canal is completely sealed, there is no howling sound. Therefore, please use hearing aids after cleaning your ear canal, and test the earplugs from large to small to find the most suitable earplugs. 3. After the hearing aid enters the ear canal, it is recommended to push the hearing aid with your fingers and hold it for 1-2 seconds, and then release it to fully extend the earplug. In addition: If you do not know how to use it or there is a problem with your hearing aid, please do not rush to leave a negative review and contact us. Thank you. Feature 1. Peak Gain(dB): 45dB,Suitable for mild to moderate hearing loss (Reference hearing loss map) 2. Upgrade digital chip: More professional sound processing chip, 4 modes of noise reduction, more clearer and realistic sound. 3. The catheter can be cut and adjusted according to the actual situation of the individual. 4. High quality: Adjustable and replaceable silicone hose, binaural universal.Suitable for different ages users. 5. Rechargeable: Charging 4-6 hours, working up to 80 hours.Saves your trouble to buy button batteries frequently. 6. If the ear dome is not completely fill into ear canal or air leaks at the ear dome, which will causes a annoying whistle.We give 3 different sizes of earplugs to reduce howling and noise. 7. Gift bundled: We will give a hearing aid box to carry.Every set contains charger, earbuds and cleaning brush etc.Will be great gifts for your friends or families. Product parameters Peak OSPL 90 ( dB SPL): 130dB HAF OSPL 90 ( dB SPL): 120dB Peak Gain(dB) : 45dB HAF/FOG Gain (dB) : 38dB Frequency range(Hz) : 300-5000Hz Distortion: 500Hz : 3% 800Hz : 2% 1600Hz: 1% Specification Product Name: BTE Hearing Aid Color: Blue/Beige Charge head: US Plug/EU Plug Weight: Total 115g Package included 1 × Hearing aid 1 × Storage box 4 × Earmuffs(different sizes) 1 × Charging cable 1 × Charging head 1 × Cleaning Brush 1 × Instructions (Please make sure has read the manual before using). Instructions 1. Clean the ear canal before use. 2. Charge the hearing aid,turn the botton to N. 3. When using it for the first time, please turn the volume to the minimum and then slowly increase it. 4. Try and select suitable ear dome. Install the ear dome and make sure it fits snugly. 5. Insert the hearing aid into the ear canal,adjust its position in the ear canal until the soft eartip is fully deployed and fill the ear canal. Notice 1. If the earbuds cannot fill the ear canal, it may cause feedback or whistler,So repeat step 5 to reduce howling and noise. 2. Turn off the hearing aid if you don't use it. 3. Please use the original charging head and charging cable for charging. Otherwise the product may be damaged. 4. If you need to use a replacement charger, please use a charger suitable for the product. If an inappropriate charger is used to charge the product, it will cause damage to the product. Charger INPUT: AC100-240V, 50-60Hz / 0.15A Charger OUTPUT: 5V, 1000mA