Andoer Cherub G-Tone GT-6 Acoustic Guitar Preamp Piezo Pickup 3-Band EQ Equal. Tone and volume control. With phase and tuner function, built-in reverb, delay, chrous and wide effects. 3-band equalizer, rotate Low/Middle/High to adjust volume frequency. Rotate Reverb/Delay/Chorous/Wide button to adjust its corresponding reverb, delay, chrous and wide effect. Wide frequency range from 20 HZ to 20 kHZ.