INGCO Test Pencil Voltage Tester - Orange... Ingco Test Pencil Voltage Tester Voltage detection: It can typically detect AC voltage from 100 to 500 volts. Compact design: The tester is small and lightweight, making it easy to carry and use. Probe tip: It has a pointed probe tip that can be inserted into wires or outlets to check for voltage. Neon indicator light: If voltage is detected, a neon light will illuminate on the tester.