Premium Quality The handle of the tester is made of AS plastic and the probe is made of quenched and tempered carbon steel with chrome plated. The sharp steel probe easily pierces wire insulation to check circuits. Long spring wireLong spring wire can stretch about 1 meters, and the wire is thickened so that the wire will not burn when the room temperature is increased. Wide Circuit TestingThis probe pen is ideal for checking automotive circuits, fuses, switches and wiring, trailers, boats, motorcycles and other low-voltage systems. Tester bulbThe light in the handle turns on when the circuit connection is complete, and this 3 watt bulb is replaceable, you can change the bulb easily. 6V-24V test rangeElectrical circuit tester is designed for checking 6V - 24V car electrical circuits. Lightweight design and super convenient to carry, you can take it wherever you go.