The AC71 is a digital clamp multimeter with two additional unique features: AutoTect and automatic backlight. The 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. The automatic backlight has a sensor that recognizes when the ambient light becomes dim and turns itself on. A bright blue backlight is then available to easily read the measurement value on the digital display. The AC71 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. Autotect The AC71 offers the AutoTect feature. AutoTect checks the signal received across the two test lead points and automatically determines the type of measurement to be made. It senses whether AC Volts, DC Volts, Resistance or Continuity is across the test nodes. 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.