• Precip is a coating. It is a microporous polyurethane that is impregnated with silicon dioxide particles. These particles create small, numerous, very consistent holes that allow the barrier to pass small water vapor molecules but not the bigger liquid ones. This keeps the rain out while letting your sweat vapor work its way outside, away from your body, to keep you dry from the inside as well as from the outside.
    Answered on 11/2/2010 12:00:00 AM by Customer Care from Sierra Trading Post