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 ReceiverÛªs 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-Foot and 20-Foot lead adapters, AC plug leads, instructions, all required batteries, and a hard carrying case with handle for convenient transportation and storage.