Providing crystal clear, sparkling water at an economical price, it the Perflex D.E. Filters have been proven reliability, and energy savings over many years, Perflex has set the standard in swimming pool filtration by incorporating the patented Flex-Tube™ design in combination with D.E. filter powder – the most efficient dirt remover known for pool filtration. The result is superior water clarity, extended filter cleaning cycles – and no backwashing required. XStream Full-Flo Cartridge Filter