Amplifier Probe, Battery: (1) 9 V Battery (Included), Battery Life: 50 HR Typical (Alkaline, 540 Milamp-HR), Probe Tip Resistance : 1000 Ohm Min, Input Impedance: 5.7 Mohm, Voltage Gain: 37 DB, Dimensions: 9.2 In X 1.7 In X 1.2 In, Weight: 5 Oz (Including Battery), Designed to Identify and Trace Wires or Cables Within A Group Without Damaging The Insulation