The Electro-Harmonix 2020 V2 Mini Pedal Tuner is a super compact and high-visibility tuner for your pedalboard. Now with switchable true or buffered bypass. The EHX-2020-2.0 Pedal Tuner is super compact and minimizes space on your crowded pedalboard. Switchable True Bypass or Buffered Bypass for easy integration into any rig, while its plus or minus 1 cent tuning range and high visibility display provide an accurate, convenient solution to all your tuning needs.FootswitchPressing the Footswitch toggles between bypass and tuner functionality. When the tuner is engaged, the output signal is muted.Buffer Off or On SwitchLocated next to the DC 9V power jack, this switch selects between passive bypass and buffered bypass. Set it to the On position for buffered bypass.In JackConnect a cable from your instrument to the In jack on the tuner. Power is applied only when a plug is inserted into the In jack and proper power is present at the DC 9V power jack.DC 9V Power JackConnect the included 9VDC power supply to the DC 9V power jack. The DC 9V jack requires standard effects pedal power with power plug dimensions of 5.5 x 2.1 mm and center-negative polarity. The maximum current draw at the DC 9V jack is 15mA.Out JackConnect your amp or another effect unit to the Out Jack. When the tuner is off, the Out jack outputs the signal of the instrument connected to the In jack. When the tuner is activated, the Out jack mutes sound output-allowing for silent tuning.Pitch ButtonThis button allows for changing the reference frequency. The 7-segment indicator, located to the left of the center digit, displays the current pitch setting on the first press of the Pitch button. Subsequent presses of the Pitch button change the pitch setting. The pitch range 0 to 5 translates to 440 to 445Hz; the range 6 to 9 equals 436 to 439Hz. Upon power up, the default setting is 440Hz.Flat ButtonThis button cycles through three flat tuning options plus normal tuning. The flat indicator is located to the left of the center digit. The first press of the Flat button displays the current flat setting; subsequent presses of the Flat button change the flat setting. Upon power-up, the default setting is Normal Tuning.