Korpa 
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.
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.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.
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. 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).
