Reach for the Pentair Pentek ECP20-20BB Big Blue Pleated Cellulose Polyester Sediment Filter when it s time to change the filter in your 20 heavy duty whole home water filtration system. This filter is manufactured from a special formulation of resin-impregnated cellulose and polyester fibers. This unique blend of materials provides a higher wet strength than regular cellulose cartridges. It also provides high flow rates and dirt-holding capacity while maintaining extremely low pressure drop.