Made especially for caravans, motor homes and boats but also ideal for summer houses, beach huts, sheds, conservatories, homes Keeps unwanted moisture and condensation under control Protects against musty odours and mildew Extra large 5 litre capacity — can be left for months without checking Use all year round Use with Damp Buster refills (not supplied). Calcium Chloride Crystals absorb the water vapour from the air. Absorbs up to 3 times its own weight in water, each refill pack can absorb up to 3.5 litres of water and lasts up to 4 months As the moisture is drawn from the air, it collects on the surface of the crystals and then drips into the bottom of the container Moisture removed from the air is converted to brine and can be safely disposed of.