Circuit Tester with Digital LCD Display to Accurately Show DC Voltage. Two LEDs Provide 360° Visibility of Polarity. The probe is insulated to prevent the possibility of shorting the side of the probe to other components. Computer safe. Will not damage sensitive electronic components. Not for use on airbags. Operating range 3-30 volts DC to work on most vehicle electrical systems. 47" cord and heavy-duty alligator clamp for secure connections.