Tuning Fork is a free Android app developed by UMEZAWA Takeshi that serves as a simple tone generator. The app offers four waveform options: sine, square, triangle, and sawtooth, providing users with versatile sound options. The frequency can be set in various ways, including 0.1Hz step, semitone step, specifying frequency directly, swiping frequency text, and a combination of standard pitch (A4) and pitch notation. This allows for precise frequency adjustment, making it a useful tool for tuning musical instruments or testing sound systems. Overall, Tuning Fork is a straightforward app that delivers what it promises, making it a practical choice for anyone in need of a reliable tone generator.