Proven over many years, Perflex has set the standard in swimming pool filtration by incorporating the Flex-Tube design in combination with diatomaceous earth, the most effective filter media available. The result is superior water clarity, extended filter cleaning cycles - and no backwashing required. Cleans pools fast - removes even the smallest particles the first time through. Patented Flex-Tube system efficiently reuses DE powder and dirt mixture to form fresh cleaning surfaces. Exclusive bump handle activates the Flex-Tubes, causing them to instantly purge themselves of dirt and powder.