The Hi-Tech line of Circuit Detectives integrate the latest technology with a simple and easy to use interface. To use the circuit breaker identifier simply plug the transmitter into the circuit you want to find, go to the breaker box and the receiver shows you the breaker you are looking for. It is almost like being in two places at once.Hi-Tech HTP-7P Professional - 90-280V Digital Includes HTP-6P receiver/transmitter Flashing arrow indicator for easier identification. Light socket adapter for finding incandescent light circuits. High impact plastic storage case for absolute protection. Fully Automatic. 250 V Operation. Includes High Voltage Leads Smart switch with auto-off, easier operation. and longer batter life