The PT-21's five primary modes are as follows: DIRECT MODE Tune by vibration sensing with PT-21 attached to instrument MIC MODE Tune by using the PT-21's on- board microphone SOUND MODE Tune listening to standard pitch from PT-21 CALIBRATION MODE Allows user to set frequency of standard pitch (A = 440 Hz at original setting) A4 pitch can be selected between 437 Hz and 445 Hz (1 Hz intervals) AUTO CALIBRATION MODE Calibrates standard pitch (A4) from an external instrument. Range is A4 (437 Hz - 445 Hz)

GUYATONE PT-21 CHROMATIC TUNER The Guyatone PT-21 is a miracle of micro technology - a multi-function chromatic tuner that fits in the palm of your hand and can be mounted practically anywhere! Designed for use with acoustic instruments, the PT-21 uses an advanced vibration sensing tuning system that allows it to function without cumbersome cables and connectors. The PT-21 mounts directly to your instrument with reusable removeable adhesive pads (included) - no modifications are required. Just stick it on, turn it on and tune! If surface mounting isn't possible with your instrument (ex: woodwinds or brass), the PT-21's onboard microphone can pick up sounds from a distance - place it on the table, on your amp, wherever, and begin to tune! Do you prefer tuning to a reference pitch? The PT-21 can generate tones over a one octave (13 notes - A4-A5) range that can be adjusted at the touch of a button. All of these functions and more can be accessed quickly and easily through the PT-21's simple "One touch" calibration - no confusing menus to scroll through. All five of the PT-21's main modes of operation can be reached by pushing an easily memorized combination of the unit's Power, Mode, and Select buttons (see instructions for particular combinations). In addition, the PT-21 offers an auto power-off function that shuts the unit down after three minutes, greatly extending battery life (this function may be disabled for constant "on" operation). The PT-21's ultra-bright, Digital display is easily visible even on dark stages and a user-selectable option of "Bar" or "Dot" tuning indicators is available for its two color, 9-segment LED display. Like all Guyatone products, the PT-21 is made In Japan and is covered by a full 3-year warranty. The PT-21 comes complete with Lithium battery, mounting adhesives, and an impact resistant plastic storage case.