'-It is a comprehensive 6-24V DC test kit. -Its long cable makes your testing easily. -It allows you to track and locate short circuits. -It can also test for continuity with the assistance of its auxiliary ground lead. -The unit has short-circuit protection and can test for bad ground contacts instantly. -The unit is the best electrical tester for reducing diagnostic time in automotive electrical systems. -After a simple hook-up of the unit to the vehicles battery, automotive technician can conduct a positive or negative battery current to the tip by rocking the power switch forward or backward. -Overload Protection --Buzzer Warning.The test pen has overload power-off protection. If the current is too large or the load is too heavv during the power distribution process.the test pen will be disconnected to protect the battery and a beep warning. -Double Insulation Protection. Safe and reliable measurement The instrument uses insulation material national safety compulsory certification (CCC). Specification: Name: Circuit Finder Tester; Operation Voltage: 6-24V DC; Material Type: plastic and metal; Item Width: 20mm/0.79inch; Item Length: 220mm/8.66inch; Lead Length: approximately 4M /157.5inch; Item Type: Electrical Testers & Test Leads; Overload protection: 8A (When the current exceeds 8A, this item will disconnect the current automatically.); Function: Polarity Testing / Continuity Testing  /Testing Components in Vehicles Electrical System / Grounding Testing / Short Circuit Following and Locating / Checking Short Circuit; Automatic Identification of Positive and Negative: -LED light prompt, quickly identify positive and negative. -LED light is bright green, Indicates the probe output positive voltage or the probe test is the negative voltage. -LED light is red, Indicates that the probe outputs a negative voltage or the probe is tested as a positive voltage. Testing: 1.Polarity Testing This tool can test uncertain polarity of contact in the circuit of vehicle. -Unroll the leads. -Connect red clip to positive terminal of vehicles battery. -Connect black clip to negative terminal of vehicles battery. -Contact the probe tip to a positive (+), the LED should light RED. -Contact the probe tip to a negative (-), the LED should light GREEN. 2. Continuity Testing -Unroll the leads. -Connect red clip to positive terminal of vehicles battery. -Connect black clip to negative terminal of vehicles battery. -Connect auxiliary ground lead to one side of tested wire along with probe tip connecting to the other side. When continuity is present,the LED will light GREEN. If LED does not light up, no continuity present. 3.Testing Components Out of Vehicles Electrical System -Unroll the leads. -Connect red clip to positive terminal of vehicles battery. -Connect black clip to negative terminal of vehicles battery. -Connect auxiliary ground lead to negative terminal of tested component. -Press button to (-) side with LED lighting RED. Contact the probe tip to positive terminal of tested component to active the component.If LED turns to GREEN with buzzer sounding, stop testing and check the component if defective or not, or rating current of component is higher than that of this tester. 4.