Andoer EQLC-4 4-Band EQ Equalizer System Acoustic Guitar Preamp Piezo Pickup LCD Screen Tuner With this equalizer, you spend less time tweaking controls and more time playing. Shape sound and eliminate feedback with 4 bands of equalization. With bass, middle, treble, pres control knobs. Wide frequency range from 20 HZ to 20 kHZ. Easy to read metronome on LCD display.