This rechargeable mini dehumidifier from Meaco contains silica gel which helps absorb moisture from the air. Place upright on a flat surface and do not cover. When the silica gel in the window is orange the dehumidifier is fully charged, when the silica turns green the unit needs recharging. Connection to the mains is only required whilst recharging. A metal plate inside the dehumidifier warms the silica gel to dry it out. Therefore unit will become warm whilst plugged in to the mains. Turning the unit upside down during charging will result in a faster drying out time.