[PROFESSIONAL TOOL]: AUTOAND circuit tester can quickly and efficiently test the automotive circuit system, effectively shortening the test time. It supports 12-24 volt cars, boats, trailers, truck, ATVs, RVs and other vehicles. [4 TESTING MODES]: There are 4 modes to diagnose the electrical systems, which can be accessed by depressing the mode button and cycling through each one: DC Voltage Test, AC VoltageTest, Resistance Test and DiodeTest. [CURRENT OVERLOAD PROTECTION]: When the current is overloaded, the car circuit tester will automatically disconnect the protection circuit, making our products durable. In addition, we provide a sturdy blow-molded outer box to store the product. [10M EXTENSION CABLE & LIGHTING DESIGN]:The 10m extra-long cable allows you to easily and conveniently inspect the entire circuit system of the car. Built-in LED light can help you complete circuit testing in a dark environment. [MULTI-LANGUAGES & WARRANTY]: Support 7 kinds of languages: English, German, Spanish, French, Italian, Russian, Portuguese. To ensure your shopping experience, we freely provide 2 years warranty and 24h e-mail support for this main unit. Please purchase it without worry.