Ptarmigan Ultralight Coat
Venturi is an impervious membrane through which no wind or water can penetrate. The laminate is breathable as it has both coarse and fine molecular structures and moisturevapour can escape through the coarser structures. The structure of Venturi shows coarse and fine molecule combinations. The water vapour can escape through the coarse molecular structure provided a water vapour gradient exists i.e. the water vapour molecule wanders from the place of greater concentration to where the concentration is lower. A second prerequisite is a temperature gradient i.e. the outer temperature must be lower than the temperature in the garment. This water vapour transport is known as breathability.