about this project Powerful Circuit TesterKAISAL car circuit tester is suitable for all car electrical systems from 5-30V. Such as polarity identification, voltage test, fuse detection, local area network circuit test, poor grounding inspection, short circuit tracking and positioning, pulse signal test, etc. This probe tester will help you trace problem lines easily and accurately. LED Digital Display & Test BulbThe car electrical tester has a real-time voltage display, which can quickly and accurately read the current voltage value. In addition, the brightness of the light bulb at the end of the circuit probe pen will change with the strength of the voltage, so that the failure of the circuit power supply can be quickly judged. Polarity Tester & Frequency PredictionThe car fuse tester quickly distinguishes positive and negative polarity by the red and green of the built-in LED. The frequency range can be estimated from the digital on-screen display when the pen is connected to a 5 to 30V AC signal. It can be used to measure fuel injector signals, spark plugs, crankshaft sensor signals, etc. Three Working ModesThe car test light is designed with a switch and a 12V 5W test bulb, so you can easily change the working mode you want. You can choose the LED digital display and the bulb to work at the same time, or you can choose one of them to test the voltage and accurately diagnose the faulty battery or fuse circuit. Easy to Use and Wide ApplicationThe car voltage tester comes with large and strong alligator clips for easy one-handed operation. Sharp stainless steel probe with protective rubber tip for piercing wire, also suitable for hard-to-reach narrow areas. The car tester is widely used in voltage tester, car fuse tester, car battery tester, probe tester, perfect for all kinds of cars, trailers, vans, RVs, motorcycles, boats, etc.