Hog 20 Watt Recharging Portable Amp The Hog-20s front panel features include volume, tone and "squeal" overdrive/distortion controls, and a standard " input jack. The rear panel has a " headphone out jack which allows the user to plug in headphones (switching off the speaker). This jack can also be used as an output for directing low-level signal to another amplifier or direct to a recording console. Two inputs (one on the front and one in the back) are included. Includes the Rechargeable battery.