Sondes are self-contained waterproof transmitters that allow the tracing of non-metallic pipes, drains and conduits.
There are many Sondes available depending on the application and the depth of the pipework. Sondes are screwed onto the end of a set of drain rods or conduits threading rod, inserted into the pipe to be traced and propelled along the pipe.
An operator on the surface can follow the movement of the sonde using a CAT receiver. If the purpose of the procedure is to find a pipe collapse, the movement of the sonde will stop at the point of blockage and the signal radiating at the point will indicate where to dig to repair the pipe damage.