For areas of up to 160 sq ft (15 sqm). Moisture Absorber: Humydry crystals absorb excess moisture from the atmosphere, until the recommended relative humidity level of 50-60% is reached. The liquid begins to drip into the lower compart ment where it is collected. When the crystals have all been used up, the liquid collected and the crystal bag can be disposed of. Replace with a new 450 g Humydry refill. Lasts for several months depending on degree of humidity and temperature. Works without electricity or batteries. Lasts for 1-3 months. www.humydry.com. Made in Spain.