Ecofiltro produces a filter used to purify contaminated drinking water. Made of clay, sawdust and colloidal silver, it is an effective, economic and ecological alternative to water purification. With its controlled pore size, it allows water to pass, but traps bacteria, parasitic cysts and faecal residues. It eliminates smell and colour, and keeps water refreshingly cool. It can be produced in any developing country. Filters are sold to urban populations at a profit, which allows the company to lower costs for rural populations.