Automatically finds the correct circuit breaker of any standard 120V outlet. Does not require interruption of service. Bright green arrow and loud tone provide clear indication of correct breaker. Transmitter reaches distances up to 1000'. Finds breaker for light fixtures and bare wires with optional adapter set. 90V to 120V operation. Auto power Off feature. LED worklight. Uses (1) 9V battery for receiver, included. UL listed for indoor use only.