A high porosity design helps the cartridge from plugging before its adsorption capacity is exhausted, maximizing the utilization of the carbon while maintaining low pressure drop. These cartridges are protected by a uniquely formulated polyolefin bilaminate pre-filter, designed to significantly increase the useful life of the cartridge by trapping sediment that typically plugs carbon block cartridges. EP Series Cartridges make an ideal choice for a wide range of residential, food service, commercial and industrial applications. Pentair Pentek SW-4 Spanner Wrench for 20 Big White Housings The Pentek SW-4 Filter wrench is a durable and simple filter housing removal tool that will make changing filters easier.