A Tinnitus masker 

For those who suffer from tinnitus, external and artificial sounds from a masker can be preferable to the constant ringing they experience.

A tinnitus Masker is an electronic hearing aid device that generates and emits broad-band or narrow-band noise at low levels, designed to mask the presence of tinnitus.

Such masking noise is also referred to as white noise. For an individual suffering from both hearing loss and tinnitus, the masker and the hearing aid can operate together as one instrument.

Would a masker be appropriate for you?

Stand next to a faucet on full blast. If you only hear the water, and not the ringing in your ears, chances are a masker could benefit you.

Regular- vs. open hearing aids

Earlier types of hearing aids closed off the ear entirely and left the patient hearing strange hollow sounds, such as amplified chewing sounds and, at times, even their tinnitus.
However, regular hearing aids may help with tinnitus for some people. Since tinnitus can be brought on by hearing loss, the brain may compensate for the lack of sound input by making its own sound effects.
An open hearing aid increases the information available to the brain by picking up background sounds around you, and can therefore also mask tinnitus.
The new types of open hearing aid are so thin, that the hollow sound is eliminated, while still allowing sounds from the outside to pass into the ear.

Source: www.berlingske.dk, www.chk-sja.dk