Elanwell portable water filter is designed for outdoor and emegency use. It remove virus, bacteria, odor, and hazardous matters in water and turns stream, lake water into directly drinkable water. It is easy to filter water by squeezing the water bag, or just by sucking water through the filter directly. Model M-101P even has an extra USB pump (powered by AA batteries or power bank) for supplying big water flow easily and especially suitable for group use.