Hayward® Perflex® EC40C80S 20 SqFt DE Filter with Base and Hose Kit. Perflex filters are performance matched with our above-ground pump series to ensure a system that maximizes its filtration ability. These advanced filtration systems are designed to operate with less resistance than conventional units, producing more filtered water with less pump horsepower. Quality, value, dependability and sparkling clear pool water are the Perflex system trademarks.