Digital Circuit Breaker Finder. 90-120V Operation. Test GFCI devices. Transmitter incorporates a GFCI outlet tester to inspect the wiring condition at the electrical outlet and test the GFCI devices. Power On indicator. The transmitter is connected to the electrical outlet or fixture in the circuit while the receiver is used to scan the breakers in the circuit breaker panel. Transmitter includes an integrated GFCI outlet tester.