【All-in-One Automotive Circuit Diagnostic Tool】 Covers 10+ core test functions: voltage & polarity detection, continuity testing, component activation, ground wire inspection, short circuit locating, trailer light connection test, etc. One-stop solution for vehicle electrical system diagnosis. 【Accurate Digital Display & Intuitive Polarity Indicator】 Precisely detects 12V-24V circuit voltage with clear digital readout. Built-in red/green polarity LED lights, you can instantly identify positive/negative circuits at a glance, eliminating guesswork for fault checking. 【Efficient Component Activation & Fault Locating】 Supports activating components in-hand, in-vehicle, and with ground. Helps you quickly locate short circuits, bad ground contacts and faulty circuits, greatly improving auto repair and maintenance efficiency. 【User-Friendly Design for All Users】 Simple plug-and-play operation, no complicated gear shifting, easy to master for both professional mechanics and entry-level DIY enthusiasts. Built-in bright flashlight for dark environments, with long flexible cable for convenient operation. 【Wide 12V-24V Universal Compatibility】 Fits all 12V-24V vehicles, including cars, SUVs, trucks, motorcycles, boats, buses and more. A must-have tool for daily vehicle maintenance, auto repair workshops, and roadside emergency checks.