The UPSTREAM's patented upflow design means constant automatic media backwash without requiring electricity. Unique blend of red flint, KDF55, and catalytic carbon deliver superior filter performance, filtering particulates, heavy metals, chlorine, VOCs, PFOS/PFAS, and more! Replacing the pre-filter takes only seconds thanks to the top loading filter housing. Push fit adapters and integrated distributor design make installation easier than ever. XS size convenient for small spaces and/or limited usage.