- Effortless System Testing: Featuring a wide detection range and a 13.5-foot cable, this test pen simplifies the diagnosis of various electrical systems, making it ideal for both professionals and DIY enthusiasts. - Versatile Applications: Seamlessly test voltage polarity, assess motors, inspect bulbs, evaluate conductivity, and trace short circuits across different automotive applications with precision and ease. - Safety-First Design: Equipped with a built-in short circuit protection mechanism, this tool ensures reliable testing and immediate detection of poor ground connections, allowing for safe and frequent use. - User-Friendly Operation: Simply connect the voltage tester pen to the car battery, then shake the handle to switch between positive and negative polarity, providing straightforward polarity readings from the battery to the tip. Use Scenarios: 1. Quickly diagnose a vehicle's electrical malfunction by testing the battery voltage polarity and identifying short circuits, saving you time and ensuring efficient repairs. 2. Check the functionality of automotive lights and motors by examining conductivity, ensuring all components are performing correctly before hitting the road. This test pen combines functionality, safety, and friendliness in design, making it an essential tool for any automotive toolkit.