Tone Generator generates sine, square, sawtooth and triangle tone at a large frequency range. Frequency of the tones can be adjusted by swiping up or down on the screen. Tone Generator has a built-in feature to quickly sweep frequency of a sine tone to test your hearing. This feature is purely for fun and should not be used for any diagnostics. Tone Generator can also help remove dust and water from device's speakerphone by playing tones at various frequencies.