Safe And High-quality: Our tester pen is composed of a high-quality and durable PVC Handle, screw rod, slotted point screwdriver, nut, spring, neon bulb tube, and resistance block, which ensure safety while using Bright Light Waterproof: The pen is designed with a bright LED light, which is also an obvious cue when used during the day. What?s more, it is waterproof, which allows you to work well outdoors. Automatically Induction: As long as it is close to the insulation of the wire, the plastic shell of the electrical appliance, etc., when the light is on, it means that the line is live. The brighter the light, the higher the voltage of the tested circuit, and vice versa. Self Check Function: In self-check before use, please hold the pen tip with one hand and touch the tail with the other hand. When the light is on, it means the tester pen is normal and has sufficient power. No light indicates that the battery needs to be replaced. Find Line Breakpoints: One hand touches the bottom of the pen, and the tip of the pen touches the wire. The break point is where the light goes out. It is used to find breakpoints in daily household appliances such as rice cookers, computers, and plug-in boards, etc. Color:Silver Size15.5cm in length Package include2*Responsive Electric Test Pen(no battery)