Outer Codex
Removes pathogens and most chemical contaminants without pumps, power, or chemistry. Gravity does the work.
The home filter stays on the counter; this one weighs almost nothing and goes in every pack. It makes stream, lake, or tap water safe to drink, and one filter lasts a lifetime.
A 1mm rainfall on a 50m² roof drops 50 litres into the barrel: the cheapest water you'll ever have.
When you can't boil and can't filter, a tablet still makes water safe to drink. It needs no power, fits in a pocket, and keeps for years.
