The Fisher Labs TW82P Single Frequency Digital Underground Line Tracer with Passive Receiver is an easy-to-use single frequency and passive power one-button locating system designed to trace all conductive lines including pipes, cables and conductive electrical lines. Its ultra-fast target response ensures fast and accurate locating. The transmitter utilizes automatic load impedance matching to adjust output signal for best power output for the ground conditions. The TW82P is weatherproof and impact-resistant, and features sealed, thick-wall, injection-molded construction.

The TW82P is used to locate and trace buried utilities using four tracing methods: conductive, inductive, via coupling clamp, and passive power. The conductive method uses the accompanying transmitter to energize the buried utility by making a direct electrical connection to it with conductive tracing cables. In most cases, this method sets up the strongest magnetic field for the receiver to sense above ground. The inductive method is ideal for when a direct physical connection to the utility is unavailable. The utility may be energized indirectly by magnetically coupling an energizing current from the accompanying transmitter. The coupling clamp method is for use when a utility may be exposed, but does not provide a direct connection for the conductive tracing cables. The accessory coupling clamp can be clamped around the exposed utility to magnetically couple an energizing current from the accompanying transmitter into the utility. Passive power mode allows the TW82P to detect the electric current of underground power lines and also on underground utilities that are not power lines using the receiver as a stand-alone instrument without need for a transmitter.

Signal strength is strongly influenced by the depth of the utility. Audio signal will decrease in volume further away from the utility, will increase in volume closer to the utility, and will be silent when directly over the utility. Rotational arrows on the display indicate the utility's path relative to the user's position.