Specification: Receiver Type:UT25A / B Operating Voltage: 90-120V Operating Frequency: 50-60Hz Power Supply: 1 x 9V Battery(Not Included) Operating Temperature: 5℃-40℃ Storage Temperature: -20℃-60℃ Transmitter Working Voltage: 110-125V Operating Frequency: 50-60Hz Fuse: 1A, 250V, 4x11mm(dia) Receiver Size(appr.): 19 x 5 x 3cm / 7.5 x 2.0 x 1.2" Package Weight(appr.): 262g Package Included: 1 x Circuit Breaker Finder (Receiver) 1 x Socket Tester (Transmitter) 1 x User Manual Quickly And Accurately Capable of detecting the open wiring fault with open ground, reverse polarity, open hot, open neutral, hot/neutral reversed wires. Great gift for any electrician, or handyman that dabbles in electrical work. With Audible Beeping & LED Indicator This circuit breaker tester with features visual flashing light and an audible beeping to alert you when the correct breaker is identified. The operator can identify the state of the connection of the circuit according to 3 LED light.