The GA-40 Electronic Guitar and Bass Tuner is equipped with an output jack so you can leave your amp plugged in. An ultra-large LCD screen provides excellent visibility. Adjustable calibration range (410-480Hz). Tunes 6 & 7 string guitars and 4-, 5-, and 6-string basses. Pure major/minor 3rd pitch indication marks. Includes reference tone, microphone, speaker, folding stand, auto power off, memory backup, and batteries. This chromatic auto-tuner works with all types of instruments.Dedicated guitar and bass tuner with large LCD for easy viewing </ BR> The GA-40 is a dedicated, easy-to-operate guitar/bass tuner with automatic pitch detection. In Guitar mode it supports seven-string guitars (7B through 1E), and in Bass mode it supports six-string basses (Low-B and Hi-C). With the precision you expect from KORG, the GA-40 indicates the pitch quickly and accurately. The LCD needle-style display provides both the accuracy of an LCD as well as the easy viewing of a needle indicator, and the display has been enlarged for even better visibility. You can also use the built-in high-sensitivity microphone to tune an acoustic guitar.Sound Out function produces a reference tone from the internal speaker </ BR> In addition to letting you tune visually using the meter, the GA-40 provides a Sound Out function that plays a reference tone through the internal speaker, letting you tune by ear. Each time you press the Sound switch, the tone will cycle through 7B_6E_5A_4D_3G_2B_1E in Guitar mode, or through LB_4E_3A_2D_1G_HC in Bass mode.Quinta Flat Tuning mode </ BR> To support the dropped tunings used in heavy metal styles to produce a powerfully massive sound, the GA-40 provides a Quinta Flat Tuning mode that lets you detect dropped tunings of one through five semitones. This lets you tune super-long scale guitars that extend below the pitch range of conventional guitars.Conveniently thin and compact </ BR> The GA-40 gives you convenient guitar and bass tuning functionality in a pocket-sized package, making it easy to tune whether you're on stage or in the studio. An output jack (bypass) has been added, making it easy to check the tuning even while you're performing.The stand on the back lets you place the tuner on any surface.Auto Power Off function </ BR> The Auto Power Off function automatically turns the power off after the unit has been left on for twenty minutes, preventing the batteries from running down needlessly.Approximately 85 hours of continuous use </ BR> The GA-40 is designed for long battery life, and allows approximately 85 hours of continuous use (continuous A4 input, Meter mode, zinc-carbon batteries).*Even if a sound is within the detectable pitch range, detection may be unsuccessful for instrumental sounds that contain a large number of overtones or that decay rapidly.Korg tuners and metronomes purchased from a Korg USA authorized dealer now have a three year warranty.