Pentek EP-20 # 155529 EP20 Carbon Block Replacement Water Filter Cartridge Compatible With Culligan / Ametek / US Filter / Plymouth / Kleen Plus / American Plumber / Bruner & Many Other Brands. 5 Micron Carbon Block Water Filter. 20" long X 2 1/2" diameter. 6 per case, sold individually. Ametek # 155529 EP Series cartridges are versatile and combine the long life of carbon block filtration with the higher dirt-loading tolerance of wound, carbon-impregnated paper cartridges like our C-1. EP Series cartridges are manufactured using a patented process that yields a cartridge with a nominal 5 micron filtration rating, high porosity and greater chlorine removal capacity. The high porosity design helps prevent the cartridge from plugging before its adsorption capability is exhausted, maximizing the utilization of the carbon while maintaining low pressure drop. Order a case and save even more.