?LED Digital Display?: This automotive circuit tester with LED digital voltage display for accurate volt readouts. Compared with LCD lights, LED lights are not affected by the brightness of light, so that be clearly read in daytime or dark areas. ?Extended Spring Wire with Alligator Clip?: Maximum extended to 110 inch long enough spring wire increases flexibility and a wide measuring area when testing, anti-bending design of the tail wire makes no worry about bad contact of the line. Along with large size alligator clip for easy one-hand operation. ?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. ?Computer Save?: This premium car fuse tester has a built-in circuit board chip, safer and more durable than traditional test lights. Equipped with insulation protective cover, it provides better grip and insulation protection against electric shock. This circuit board with line protection function, which is safer and more burn-resistant. ?Widely Use?: This auto electric tester pen is ideal for checking various vehicles electrical circuits. Sharp long probe is used to pierce wires and reach into narrow areas, quickly check automotive headlights, taillights, turn signal circuits, faulty sockets, connections, fuses, broken wires and more, suitable for your daily use.