It's a high-efficiency filter and heat exchange system. Perspiration passes through the first layer and is gathered in the second. The salt is separated. Breathing and walking provide the pumping action. The reclaimed water circulates to catchpockets from which you can drink through this tube at your neck. Urine and feces are processed in the thigh pads. Should you be in the open desert remember to breathe in through your mouth out through the nose tubes.