The Navigator comes in two models. One for concrete and one for vinyl pools. It has a preprogrammed steering which alternates in a series of left and right turns to get all the areas of the pool. If adequate suction is provided, the Navigator will fly up the walls of the pool to clean also. Although it does not handle twigs and large leaves well, it does a pretty good job. If it runs into a pile of acorns or large amount of leaves it can get clogged fairly easy. Works well in screen in areas or pools without a lot of leaves and debris. It requires 1” of vacuum for every length of hose so care must be taken to make sure your pool pump has adequate suction to run the cleaner.