What's the difference between a camping gravity filter and a countertop gravity system?

Camping gravity filters (like the Platypus GravityWorks and Katadyn BeFree) use lightweight collapsible reservoirs and hollow-fiber cartridges aimed at bacteria and protozoa for backcountry use. Countertop systems (Big Berkey, Waterdrop TK-FS, Purewell) use stainless-steel housings and denser carbon/ceramic elements that also target chlorine taste, lead, and other tap-water contaminants. Pick based on whether you're filtering trail water or improving home tap water.