Tuning Procedure: 1.Press the power button and hold 2 seconds to turn on (off) the tuner. 2.Press the power button continuously to select tuning mode out of Chromatic, Guitar, Bass, Violin and Ukulele. 3.Clip the tuner onto your instrument. 4.Play a single note on your instrument, the note name (and string number) will appear in the display, the screen color will change, and the meter moves. Back light turns green;and meter stands in the middle:note in tune Back light stay white;the meter points to left or right:flat or sharp note Features : Quality environmental-friendly ABS applied, Scientific design with exquisite workmanship ensure no break in use. Very simple to operate,only one button controls everything:turn on /off and setting tuning modes according to your instruments. The tuner head turns 360 degrees for any reviewing angle for your easy reading; Auto off for no signal detected for 3 minutes to save energy. Specifications: Tuning range: A0(27.5Hz)~C8(4186Hz) Tuning scale: Chromatic, Guitar, Bass, Violin, Ukulele, Banjo, Mandolin Precision: ±3Cent A4: 430Hz- 450Hz Color: Black Power Supply: 3V LCD dimention:0.79x0.9 inch Demensions: 1.1(W)x1.46(D)x1.89(H)inch Weight: 0.06 lb YOU WILL GET: 1 x Tuner 1 x user manual 1 x coin battery CR2032 (Just for test, if it didn't work, kindly change a new one for use) 4 x picks