This probe pen is perfect for checking circuits, fuses, switches, and wiring in automobiles, trailers, boats, motorcycles, and other low-voltage systems. Connect the alligator clip to ground, then use the probe to test the circuit. If the indicator light is on, there is electricity. The handle is made of plastic and the hardened and tempered steel probe is chrome-plated. The sharp steel probe easily pierces wire insulation to check circuits. The light in the handle turns on when the circuit connection is complete. Test a range of circuits from 6V to 24V. and super convenient to take with you. Color: red Material: plastic Package Contents: 4 X Circuit Tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in a little different from the real thing. The measurement allowed error is +/- 1-3 cm.