These cleaners attach to one of the suction ports at the pool. Usually, this port is the skimmer, or your pool may have a separate vacuum port where the cleaner's hose can attach. With the hose attached and the filter pump running, suction is created on the underside of the cleaner. The cleaner moves randomly, or automatically around the pool with motion created by a device that gives a stop/ start pulsing of water. As the unit travels, debris is sucked up through the neck and then the hose, past the suction port, through the pipe, and stops at the filter pump strainer basket, while smaller debris passes through to the filter. Adjustments on the hose, the unit itself, and flow volume will create different cleaning patterns, so as to maximize pool coverage.