1、Operation Process: Ground the crocodile clips or chassis, then test the circuit with the probe, the probe can easily pierce the wire insulation to check the continuity of the circuit. 2、Bipolar Light Emitting Lamp: The voltage test pen uses a bipolar light emitting lamp, which is not easily damaged by heat over a long period of time, and the lamp is also very stable. 3、Stainless Steel Pin: The voltage test pen uses a retractable stainless steel pin with a flexible leading wire with good tensile strength to test automotive fuses, lamp holders, etc. 4、Easy to Use: When the circuit connection is completed, the light built into the handle of the voltage test pen will light up, which is easy to use and very friendly to novices. 5、Wide Range of Testing: The automotive voltage test pen is mainly used to check all circuits and accessories on 6V and 12V and 24V systems, and can be used on trailers, trailers, motorcycles, airplanes, etc.