JOYO JE-307 5-Band EQ Equalizer Acoustic Guitar Preamp Piezo Pickup Tuner Features: With this equalizer, you spend less time tweaking controls and more time playing. Shape sound and eliminate feedback with 5 bands of equalization. With bass, middle L/H, treble, pres control knobs. Phase and volume control. Wide frequency range from 500 HZ to 10 kHZ.