Judge the continuity of cables or wires. Track cables or wires and diagnose break point. Receive the sound signal on cables or wires (telephone line). Identify the status of the active phone line (erase, ring, busy). Send a single solid tone or dual alternating tone to the cables or wires of the object. Receiver: On / off button Test button 3.5mm headphone jack Receiver dimensions: 23 x 4 x 2.3 cm (H x W x D, approximate) Issuer: Tone / Stop / Cont switch. (Continuity) LED Tone / Cont (Continuity) Red and black test lead cable (length 61cm, approximate) Integrated RJ-11 telephone cable (length 47 cm, approximate) Sender dimensions: 6.5 x 5.6 x 2.1cm (H x W x D, approximate) Power supply: 9V battery (Not included in the package)