Dimensions (W/D/H):4.39" x 2.38" x 1.98" (110mm X 60mm X 50mm) Weight:0.68 lbs. (309g) Bypass:True Bypass Switching Power Consumption:9VDC/4mA or 18VDC/6mA Battery Type:9VDC (006P) x 1 AC Adapter (Optional):9VDC-18VDC, Negative Tips (Regulated recommended) Input Impedance:500k ohm (min) Output Impedance:10k ohm