The OEM Whirlpool and the aftermarket ClearChoice CLCH125 filters all reduce contaminants found in your water, including dirt, chlorine, lead, and other chemicals. The OEM Whirlpool filter has been tested against NSF/ANSI Standard ratings of 42 and 53, meaning it has been certified to reduce contaminants and chlorine in water. The EcoAqua EFF-6001A replacement is an aftermarket replacement filter that has comparable filtering capacity to the OEM, but at a much lower price. The EcoAqua replacement is the lowest priced 4396701 filter we offer and has many of the same features as the OEM. We recommend the EcoAqua brand due to its affordable price and filtering abilities. The primary difference between the OEM and the aftermarket filter is the price and NSF/ANSI Standard certifications, though some non-NSF/ANSI rated filters are still constructed from NSF/ANSI rated parts.