- Tester light bulb: This LED test light circuit tester bulb has high visibility and long service life. It indicates the state of the circuit. The top 3W lamp brightness changes with the measured voltage and is replaceable. - Premium quality: Automotive circuit tester probe made of metal, with a large alligator clip for convenient one-handed operation. It can reach tight areas that are hard to reach. ABS body provides superior durability over other products. A top-of-the-line 47-inch PU wire provides heat insulation, wear resistance, and tensile strength for car testing. - Wide applications: 6-24V Automotive screwdriver test light, widely used for circuit test in automobiles. This automotive tester is suitable for battery test, headlight test, brake light test, fault connections, and injector signal test, and can be used for other 6-24V circuit tests. - Bidirectional testing: Alligator clamps can be connected to either negative or positive ground, with the probe touching the other side. During positive connection the red LED is on, and during negative connection the green LED is on. - Practical use scenarios: Diagnose headlight and brake light circuits to verify voltage and connections. Check battery connections and injector signal in 6-24V systems. Reach tight areas under the hood or dash thanks to the long PU wire for grounding points and suspect connections.