17MM Pipe Camera 512Hz Transmitter and Locator Receiver Sonde Pipe Sewer Drain Camera for repair replace Receiver: The receiver has a built-in induction coil to receive the magnetic signal from the pipeline, and the coil generates an induced current to calculate the direction and position of the transmitter. There are two receiving modes: Far (note: about 5M) and Near (note: about 1 meter). Then adjust the sensitivity knob, peak mode (maximum) or null mode (minimum) to locate the transmitter.