The TW-7700 Digital Line Tracer consists of a transmitter, receiver, ground-plate/ground-rod assembly, carrying case (hard or soft), and an operators manual. The TW-7700 is a single frequency line tracer.

The TW-7700 is an active locating line tracer. There are three methods of active locating that an operator can use to trace a utility. The conductive method is the most preferred method, since a strong transmitter signal is transmitted through the intended target. The inductive method is the easiest method to use, but may not yield the best results. When a direct connection is not available, but the operator has good knowledge of where one point of the utility may be, the operator can place the Transmitter over the utility making sure that the arrow on top of the transmitter is parallel to the path of the utility. The third method of active locating involves using the coupling clamp accessory. The coupling clamp is used when the utility is exposed, but a direct connection is not available. The clamp jaws are opened and placed around the utility. The clamp never makes a direct connection with the utility, that is, the utility can move freely with the clamp around it.

The features of the TW-7700 make it a very easy and practical instrument in today's world of underground locating.