Quantity: One set (with storage box, battery not included) Receiver dimensions: 38.5 x 4 x 2.3 cm (H x W x D, approx.) Transmitter dimensions: 6.5 x 5.6 x 2.1 cm (H x W x D, approx.) DC Voltage: 6-42 Volts Operating Power Supply: 2 x 9V (6F22) Batteries Open Circuit Position: Powered by 2 x 9V batteries. 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, power leaks, and even trace wires. LEDs on both the transmitter and receiver indicate open or short circuit conditions. Check for short circuits: You can also detect intermittent circuit faults by bending wires or connectors and listening for changes in the receiver's tone, the 7-inch flexible probe helps reach wires in tight spaces. Suitable for 6~42V DC circuit power: It is suitable for various circuits with voltage between 6 and 42V DC. (For example, in cars, trucks, tractors, boats, RVs, etc. with a wide range of operating voltages.) Internal overvoltage and overload protection. Built-in buzzer sound indication in open or short circuit condition, with storage bag, easy to carry. Quick and easy diagnosis: Assess Save time by speeding up your repairs and detecting problems more easily. I = trying to figure out what's wrong with a car circuit. Good quality product