The E-500 is a passive dehumidifier using no electricity to operate it can absorb up to 8oz of moisture from enclosed spaces up to 500 cubic feet perfect for gun safes closets boats RVs pantries and more. When the unit is fully saturated (usually 3-4 weeks) the beads in the indicator window will gradually turn from their orange dry color to dark green wet color simply plug the unit ito a powerstrip in a well ventilated area for 12-18 hours to renew the renewale process may need to be repeated if the unit is overly saturated make sure to give it 45 mins of a cool down between dry cycles. The E-500 has a 5-year manufacture warranty and has a life span of 10 years.