Input impedance: Zin @ 1KHz 30K / Output impedance: Zout @ 1KHz: 33K.Power requirements: 9Vdc 10mA. The Unit runs off a standard center negative 9v DC 2.1mm Boss style adapter or a single 9v battery.Warranty InfoKeep the unit away from water, honey, and other liquids, and use only with a 9V battery or center negative 9V DC adapter.