The Highest Water Clarity with the Lowest Amount of Fuss. Quad D.E.® Filters combine the finest filtration available for the most sparkling clear water with the convenience and easy-cleaning features usually found only in a cartridge filter. Four easily accessible and removable D.E. cartridges simplify maintenance and save time.An Eco Select Brand Product: Water flows very efficiently through Quad D.E.® Filters allowing the use of smaller pumps or lower pump speeds to minimize energy use. And when consumers rinse cartridges rather than backwash, they can significantly reduce water use, too.