The Korg CA-50 is a tuner for guitars and orchestral instruments. Thanks to the large tone detection range, you can tune any instrument with this device. This is due to the built-in microphone and the frequency range from 27.5 to 4.186 Hertz. Thanks to the 6.3 millimeter input you can tune the strings of an electric (bass) guitar. You tune your instrument to a different fundamental by the calibration function. This allows you to tune your instrument in both 440 and 432 Hertz. Due to the battery life of 135 hours, the battery lasts longer than that of comparable ones. You train your hearing with the sound out function. The device produces a pure tone that you learn by heart, replay with your instrument or sing with your voice.