An affordable yet rugged solution for your Bass or Guitar pedal board and amp setup! Our GTA7800 True-Bypass Pedal Tuner allows the player to tune on stage without being heard by the audience. Features include a bright LED display for easy viewing, a durable metal case, and calibration from 436 Hz to 444 Hz. The flat option allows you to lower the reference pitch by 7 half steps. Battery power (9V Battery) as well as 9V/DC jack for power supply.