Ideal for quickly identifying individual branch circuits and wiring faults without interrupting power. Includes receptacle tester with auto sense feature. It’s now easy to identify the circuit breaker associated with any 110V AC outlet. Start by plugging the transmitter unit into any 110V GFCI or non- GFCI receptacle. After checking the outlet for several common wiring errors, the transmitter sends an RF signal down the circuit’s wires back to the breaker box. At the breaker box, begin scanning with the receiver unit. A green LED on the receiver will light, and the socket that the transmitter is plugged into will be identified. A patented circuit in the BF10 eliminates the “false positives” that weaker technologies like inductive coupling often produce.