Handle is made of plastic and the hardened & tempered carbon steel probe is chrome plated. The steel probe easily pierces wire insulation to check circuitry. Light in handle glows when circuit connection is complete. Test a range of circuits ranging from 6V to 24V. Light weight design and super convenient to bring with. This probe pen is perfect for checking circuits, fuses, switches and wiring on automobiles, trailers, boats, motorcycles and other low voltage systems. Connect the alligator clamp to the ground, then take the probe to test circuit. If the indicator light is on, there is electricity. Circuit Tester Clamp Capacity: 20A Voltage Range: 6V-24V Pen Length: 18cm Wire length: 270cm, expandable Instructions: 1. Clip the measured alligator clip to the ground wire (such as the metal or negative pole of the car) 2. Measure the conductive metal in the test circuit with the needle of the electric pen 3. If the light bulb of the stylus light up, it means that the measured point has formed a circuit and works normally. On the contrary, there is a fault at the measured point, which is to be checked. Colour:Photo Color Material:plastic Package Contents: 1 x Electric 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 the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.