Gore-Tex: A Hiker's Best Friend

A good waterproof garment is also breathable. Essentially, the theory behind making a good waterproof garment is that a water drop is larger than a molecule of water vapor. By combining waterproofness with breathability, a membrane with a pore size much smaller than a water drop but much bigger than a water vapor molecule is needed.
This is where Gore-Tex comes in! About thirty years ago, a petrochemical polymer called polytetrafluorethylene (PTFE) was developed, better-known as "Gore-Tex." Since 1976 many variations of Gore-Tex have been developed which fall under the category name of "PTFE laminates."

Many brand names use Gore-Tex these days as part of their hiking lines from Amadeus of Austria raincoats to vasque hiking boots.