It will detect and alert you immediately when the circuit is turned on.You can quickly and easily locate short circuits, open connections, broken wires, current leaks and even trace wires.LEDs on the transmitter and receiver indicate open circuit or short circuit conditions.Check for Shorts: You can also spot intermittent circuit problems by bending wires or connectors and listening to the receiver's tone changes, the flexible 7 inch probe helps reach wires in crowded areas.Suitable for 6~42V DC circuit power supply: It is suitable for various circuits with voltage between 6~42V DC.(For example in cars, trucks, tractors, boats, RVs, etc. with a wide range of operating voltages.).Internal protection against surges and overloads.Built-in buzzer sound display in open or short state, with storage bag, easy to carry.Quick and easy diagnosis: judge Save time by speeding up your repairs and detecting problems more easily.