Amprobe Automatic AC71B Clamp Multimeter is the automatic everything clamp meter. AutoTect feature automatically senses what type of measurement is being made when the test leads are placed across a measurement point. There is no knob to turn. The meter knows what is being measured and the digital display shows the measured value along with the associated unit icon. AutoTect also utilizes a lower input impedance. This helps determine if voltage is from leakage (called ghost voltages) or a hard connection. Any ghost voltages will be zeroed out by the lower input impedance. Amprobe AC71B is a complete multimeter measuring AC and DC volts, resistance, continuity in addition to the AC current. A useful tool for the electrician, plant maintenance, HVAC or field service technician.