This renewable dehumidifier uses a micro absorbing silica gel technology as a deficit to remove excess moisture from the air. The micro absorbing silica gel is a safe, non-toxic, natural defense against decay, and damage caused by excess moisture. To renew, plug the unit into a wall outlet of a well ventilated room up to 12 hours to dry out the silica gel beads. Once renewed, the indicator beads will return to orange and the unit will be ready to use again. Great for small enclosed spaces like RVs, cars, closets, and more.