1) Why there are some background noise?

Actually, it is the electric current sound existing in all good machines. Generally, the higher the power, the greater the static sound.

Turning on after put it in ears, then turn up the sound gradually. Generally, You will get used to it after 2-3 weeks.

2) What causes the squeal?

If the ear dome is not inserted well into ear canal or air leaks at the ear dome edges, when the device is close to hand or wall, a certain amount of sound will go back into the microphone. The sound is re-amplified which causes that annoying whistle.

Try and select suitable ear dome. Put the ear dome into the ear canal and make sure it fits snugly inside. Turning on the device after put it in ears.

3) Why the worked pretty well for a few days but a few days latter them do not work?

Please make sure the device were fully charged.

PLease noticed that the device that you were having problems with. Whether there is earwax on the earplug? Once you cleaned that, they will work better

Package:

2 x rechargeable hearing aids for seniors

10 x hearing aid domes

2 x USB cable

2 x adapter

2 x hearing aid cleaning brush

1 x packing box

1 x instruction manual