The Klein Tools ET450 Advanced Circuit Tracer Kit is a professional tracer for energized and non-energized breakers, fuses and wires. When the Transmitter is connected to a circuit, the Receiver's sensitivity can easily be adjusted to detect the transmitted signal on breakers, fuses and wire through drywall, cement block and underground. Kit comes with transmitter, receiver, blade and ground prongs, alligator clips, 3 ft. and 20 ft. lead adapters, AC plug leads, instructions, all required batteries and a hard carrying case with handle for convenient transportation and storage.