79406LT - 

Line Tester, 1 VAC to 150 VAC Voltage Rating

The Shurite Power Integrity Series now offers both analog and digital models with enhanced features. The 9016LFT provides switchable readings of both voltage and frequency. The 9017 alerts users to low, normal and high voltage by means of three LEDs and an audio alarm. All models plug directly into any standard AC outlet for quick reliable monitoring of voltage fluctuations and damaging brownout conditions.
It allows the user to check the voltage present at a standard home outlet. Simply insert the thru plug into any standard household wall outlet, read and note the line voltage, plug an appliance into the thru-plug and view the measurement.