Heavy-duty 5–90V digital LED circuit tester designed for quick, reliable electrical checks on cars, trucks, SUVs and boats. Key benefits Wide voltage range (5–90V): covers 12V and 24V systems and allows quick battery voltage checks and alternator/charging system diagnostics. Clear LED digital readout: provides accurate volt readings that remain readable in bright daylight or dark conditions. Fast fault finding: verifies charging system output, battery state, fuse connections and the integrity of headlights, taillights and other circuits. One-handed testing and durable wiring: long, flexible spring wire and large alligator clip let you hold the probe and clamp with minimal effort for faster, safer testing. Polarity made simple: bidirectional indicator LEDs show polarity at a glance — red = positive, green = negative — so you can clamp to either ground and probe the other side. Features Voltage range: 5–90V DC for broad compatibility with automotive and marine systems. LED digital display: stable, easy-to-read volt readouts unaffected by ambient light. Spring wire length: 106.3 inch flexible tail wire for extended reach and improved maneuverability when accessing tight or awkward areas. Large alligator (crocodile) clip: secure connection for single-handed use and quicker checks. Bidirectional LED polarity indicator: red for positive, green for negative; clip may be attached to either positive or negative ground while the probe contacts the test point. Typical uses / scenarios Pre-trip battery check: quickly verify battery voltage and alternator charging output before a long drive. Lighting and fuse troubleshooting: test headlights, taillights, fuses and wiring to isolate open circuits or poor connections. Marine and fleet maintenance: inspect boat charging systems and commercial vehicle electrical systems without swapping tools between 12V and 24V systems. How to use Attach the large alligator clip to a known ground or battery terminal (positive or negative). Touch the probe to the point you want to test. Read voltage on the LED display and note the polarity via the red/green indicator LED. What it solves Eliminates guesswork when diagnosing battery, alternator and circuit problems. Reduces time spent reaching difficult test points thanks to the long, flexible spring wire and one-handed clamp design. Improves confidence in readings with a clear, daylight-readable LED display and simple polarity indications. This heavy-duty 5–90V digital LED circuit tester combines a wide testing range, easy-to-read display, long flexible lead and polarity indicators for dependable, efficient automotive and marine electrical diagnostics.