Auto Tuning - as a note is played the tuner senses and indicates the closest note. No manual switch is necessary to select the proper notes.
Calibration - standard pitch is A440. Many tuners allow you to modify the pitch up or down in 1 Hz steps (438 Hz - 445 HZ/8 steps). Pitch changes are often necessary when tuning for compatibility with other instruments.
Chromatic - a chromatic tuner will tune to any note including sharps and flats. Therefore, a single chromatic tuner will tune virtually any instrument.
Guitar, Bass, Violin, Viola, Cello Tuners - tuners for specific instruments recognize only the notes of that particular instrument. Example: Guitar - E, A, D, G, B, E.
LED Display - multiple colored light indicators that light in different combinations to indicate when the proper note is in tune.
Line In - the input jack is used to connect directly to the pickups of electric instruments.
Line Out - the output jack is connected to the amplifier. When the tuner is not in use it can be left in-line after tuning.
Mic - a built-in microphone is provided in many tuners for tuning of acoustic instruments. The instrument is positioned as close as possible to the microphone on the tuner while tuning.
Octave - the same note at a higher or lower pitch. A multiple octave range will be recognized by the tuner.
Quartz - electronic technology that provides extremely accurate tuning capabilities.
Reference Note - a tone generator included in some tuners that sounds a note to help get your instrument up to the proper tuning range.
VU Meter - a needle style indicator that moves to the center "zero" position as the note becomes tuned.