BackBeat G1 Portable Bass Guitar Subwoofer w/ Box - UsedThe BackBeat G1 is a wearable subwoofer that you attach to your bass strap or belt. It has a transducer that shakes on a spring when you have your bass plugged into the unit that allows you to feel the low end. It has a 1 8" TRS aux input that allows you to run your music into the unit as well as a 1 8" TRS headphone out so you can hear it as well. The 1 4" in and out is where you run your bass in and then out to your amplifier or D. I. This item is