Robotic pool cleaners are self contained electric powered cleaners that are put into the pool when there is a need for cleaning. A transformer is plugged into a wall outlet and a long cord from the unit plugs into the transformer receiving low voltage power to operate the cleaner. This power operates two motors; a pump motor that draws debris into the unit's filter, and a drive motor that moves the unit around the pool. The advantage of owning a robotic cleaner is the self-contained filter bag, which can be cleaned easily. They also do quite well with coverage of the pool. Some units are computer chip controlled and some even have remote controls so you can steer the unit from a lounge chair! Being that they are the only cleaners not attached in any way to the pool's circulation system, they produce no resistance or back pressure on the filtering. Their cost can be more than suction or pressure side cleaners but the benefits are many.