All-In-One Comprehensive Automotive Electrical Diagnostic Functions Our professional circuit tester drastically cuts diagnostic time and boosts repair efficiency with full-range testing capabilities. It quickly locates bad ground contacts, traces broken wires, and performs in-depth battery health analysis (including startup, charging, and load tests). It also supports fuel injector testing and cleaning with 4 adjustable pulse modes, covering every essential need for vehicle electrical system repairs. Ultra-Wide 6-30V Compatibility for Versatile Vehicle Use Designed for all 6-30V DC/AC electrical systems, this automotive circuit tester is universally compatible with cars, trucks, motorcycles, small boats, and more. It handles all core electrical diagnostics in one tool: DC/AC voltage measurement, resistance testing, short circuit tracing, breakpoint detection, as well as fuel injector testing and cleaning, eliminating the need for multiple single-function testers. Intuitive Operation & HD TFT Display for All Users Equipped with a high-definition 160*128 DPI TFT color display and simplified tactile buttons, this tool delivers crisp, clear test results at a glance. Simply connect it to your vehicle battery via heavy-duty alligator clips, and use the integrated rocker switch to activate components without extra jumper wires. It's perfectly suitable for both professional automotive technicians and DIY car enthusiasts, with no steep learning curve. Multi-Layer Safety Protection for Risk-Free Testing We prioritize your safety and equipment security with a built-in resettable circuit breaker, which automatically trips during overload or short circuit events to prevent damage to both the tester and your vehicle's electrical system. It also features red/green LED polarity indicators and acoustic prompts, allowing you to instantly identify positive and negative circuits, ensuring safe and reliable operation throughout every test. Durable Ergonomic Design for Harsh Garage Environments Built to withstand the demands of daily professional use, this compact circuit tester (1654027MM) comes with an extra-long flexible test cable, enabling full-vehicle testing without the hassle of repeatedly searching for ground points. The probe features a built-in LED work light to illuminate dark engine compartments and hard-to-reach areas. With an operating temperature range of 0~60°C (32~140°F), it holds up perfectly in tough garage and workshop environments.