All of the 4396508 filters reduce contaminants—like dirt, rust, and lead—that are in your water supply. The Whirlpool replacement filter is the OEM product and has been certified by the NSF. The Whirlpool filter meets both NSF/ANSI standard 42 and 53, which means it is certified to reduce chlorine and remove lead, mercury, and other impurities from your water. The Supco replacement filter has many of the same features as the OEM, but at a much lower price. The aftermarket EcoAqua replacement is the most cost-effective filter and has comparable filtration results to the OEM. The primary difference between the OEM and aftermarket filters is the price and NSF/ANSI ratings, though many non-NSF/ANSI rated filters are constructed from NSF/ANSI rated parts.Even though the aftermarket filters are not NSF/ANSI certified, we recommend them due to their affordable price and excellent filtration.