A tuner is a device used to adjust the pitch of a musical instrument. It can be used to tune an instrument to itself, to another instrument, or to a reference pitch. Tuners can be electronic or mechanical, and they come in a variety of shapes and sizes. Using a tuner is essential to playing an instrument in tune, as even a slight difference in pitch can make a big difference in the sound of the instrument.
Tuners work by detecting the pitch of a sound and then displaying the note name and pitch on a display. Electronic tuners use a microphone to detect the sound, while mechanical tuners use a vibrating reed or string. The tuner will then display the note name and pitch on a display. Some tuners also have a built-in metronome, which can be used to help keep time while playing.