Hayward PHS41CST AquaNaut Suction Pool Vacuum (Automatic Pool Cleaner) V-Flex technology provides maximum power at any flow and handles any type of debris without clogging Patented adjustable roller skirt maintains constant suction on uneven surfaces and obstacles Multiple pre-programmed steering sequences ensure complete pool coverage Ideal for use with variable-speed pumps Designed with 4-wheel drive for larger pools or pools with deep ends