Self-check before use, please hold the pen tip with hand and for touch the tail with the other hand.When the light is on, it means the tester pen is normal and has sufficient power hand touches the bottom of pen, and the tip of pen touches the wire. The breakpoint is where the light goes out.Easy to hot wires As long as it is close to the insulation of the wire, the for shell of the electrical appliance, When the light is on, it means that the line is live This is a flexible tool that provides a unique ability to check holiday lights and power to they are capable of being lit and used Our tester pen is materials, practical and, Manufacturer: XIAOQENAN