Hayward Perflex® EC40AC 20 SqFt Modular DE Filter. Perflex Extended-Cycle diatomaceous earth (DE) filters provide crystal clear, sparkling water at an economical price. 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.

Requires only two nuts and bolts for easy maintenance access captures all dirt on the first pass, even removing dust, pollen and algae as small as one micron (100 times smaller than a grain of salt), lowering daily run times to reduce energy costs.