Advanced Water Filtration Technology: Our whole house water filter pack incorporates three specialized filters for comprehensive water purification. The first-stage polypropylene sediment filter (FP25B) captures particles as small as 5 microns. The second-stage FG25B-KS compound filter is tailored to eliminate a wide range of contaminants, including chlorine, chloramine, lead, mercury, hydrogen sulfide, heavy metals, PFAS, herbicides, and odors.