1. Expanded Voltage Capacity Extensive Use: heavy duty 5 90v digital led circuit tester with a wider testing range, quickly tests car battery voltage and diagnoses issues, including alternator tester functionality for car/truck/SUV/boat charging systems. Also used to inspect the integrity of headlights, taillights, fuse connections and more 2. LED Digital Display: automotive test light with LED digital voltage display for accurate volt readouts. Compared with LCD lights, LED lights are not affected by the brightness of light, so they can be clearly read in daytime or dark areas 3. Flexible Spring Wire Large Alligator Clip: automotive fuse tester. 106.3 inch long spring wire increases flexibility when testing and the anti bending design of the tail wire eliminates worries about bad line contact. Attached with a large size crocodile clip for convenient one handed operation, which boosts the efficiency for car battery capacity checks and more 4. Bidirectional Indicating Light: There is a bidirectional light emitting diode on the circuit board for polarity indication, red light indicates positive polarity green light indicates negative polarity. You can attach the alligator clamp either to negative or positive ground, while using the probe to touch the other side