1.[ Quality Made] automotive test light adopts long sharp stainless steel probe for piercing wires, also for hard to reach tight areas. Insulation protective rubber tip protects you against electric shock. Heavy duty test light body constructed with high quality ABS, shatter-proof, more durable than normal test lights. 2.[Computer Safe Accurate LED Digital Reading] Digital LED voltage display for accurate volt readouts, .1 v resolution ratio with pinpoint accuracy. Compared with LCD, clear&visible LED reading display for day and night. LED circuits board with micro current than traditional test lights, more secure and burn-resistant to automotive computer board. 3.[Wide Application Than Others] This professional automotive circuit tester/circuit test light with 3-72V DC voltage testing range, ideal for checking various vehicles electrical circuits, quickly check automotive headlights, taillights, turn signal circuits, faulty sockets, fuse connections, also for voltage testing other 3-72v DC wirings and circuits. 4.[Bidirectional Voltage Testing] You can attach the alligator clamp either to negative or positive ground, there is also a light emitting diode on the circuit board with polarity indication for easy battery load testing. Red light indicates positive polarity and green light indicates negative polarity.