It is a triple filter, which consists of 5 micron PP polypropylene on its outer surface to remove soil, sediment, etc. Coke activated carbon in a compact form of 0.5 micron to remove 100% odors, taste, chemicals, chlorine, etc. ULTRA FILTRATION membrane (UF) 0.01 micron for microbial removal. The manufacturer is certified with NSF / ANSI 42.Available in 25pcs.