Stillsuit

A stillsuit is a fictional body suit designed by the Fremen in Frank Herbert's "Dune" universe to maintain their body moisture in the harsh desert environment of the planet Arrakis.

In "Terminology of the Imperium", the glossary of the novel "Dune", Herbert provides the following definition:

STILLSUIT: body-enclosing garment invented on Arrakis. Its fabric is a micro-sandwich performing functions of heat dissipation and filter for bodily wastes. Reclaimed moisture is made available by tube from catchpockets.

The stillsuit also draws perspiration away from the body and collects it, and pumps built into the heels of the suit drive the filtering mechanism.

In "Dune", as the planetologist Liet-Kynes is assisting Duke Leto Atreides with the fitting of his stillsuit, he explains the suit in this manner:

It's basically a micro-sandwich — a high-efficiency filter and heat-exchange system. The skin-contact layer's porous. Perspiration passes through it, having cooled the body ... near-normal evaporation process. The next two layers . . . include heat exchange filaments and salt precipitators. Salt's reclaimed. Motions of the body, especially breathing and some osmotic action provide the pumping force. Reclaimed water circulates to catchpockets from which you draw it through this tube in the clip at your neck... Urine and feces are processed in the thigh pads. In the open desert, you wear this filter across your face, this tube in the nostrils with these plugs to ensure a tight fit. Breathe in through the mouth filter, out through the nose tube. With a Fremen suit in good working order, you won't lose more than a thimbleful of moisture a day..."