■Input impedance: 550KΩ ■Input impedance: 500KΩ ■Output impedance: 10KΩ ■Battery optimal voltage: 8-10 VDC (9 V alkaline battery recommended) ■External power voltage: 9VDC, center negative [ – ], power supply not included ■DC power plug barrel: Ø 5.1/2.1mm, 12mm long ■Operation time on alkaline battery: 4 to 8 hours ■Current consumption: 28-40 mAh ■Product size: Length: 120 mm, Width: 61 mm, Height: 31 mm ■Product weight: 0.25Kg ■Shipping weight: 0.40Kg