NO DAMP DEHUMIDIFIER keeps your boat or RV fresh, dry and clean smelling by absorbing more than it's own weight in humidity. When used in confined areas NO DAMP will dry the air to a level where mildew and odors cannot grow, thus protecting stored goods from damage. NO DAMP protection lasts for weeks, depending upon the level of humidity, size of area to be protected and temperature. Check weekly to pour off trapped humidity which forms as liquid water in the container. When absorption performance diminishes, re-fill ingredient may be added right on top of remaining chemical. 12oz. container treats 900 cubic feet.