T-Mask

T-Mask is a tinnitus masker.
T-Mask generates a white noise where a selected frequency can be masked.
When the masked frequency matches the frequency of the hissing/ringing caused by your tinnitus, playing back this noise masks the hissing/ringing.
A white noise runs on all frequencies we can hear. By masking only the frequency affected by the tinnitus, T-Mask allows the brain to hear all frequencies (white noise + perception of tinnitus) at the same energy: that is equivalent to not hearing the tinnitus (or to reducing its perceived intensity).