GREAT GIFT FOR THE HUNTING enthusiast Safe, non-toxic, natural defense against moisture and mildew. Renewable Eva-Dry dehumidifiers are filled with silica gel, a very thirsty substance. Odorless silica beads absorb many times their weight in moisture and lock it in so water cant leak or spill out. When the Eva-Dry is full" you renew the silica inside by plugging the unit into any power outlet. Heat gently releases water vapor in a few hours. When the indicator is blue again, Eva-Dry is renewed and ready to go back to work. You can repeat the process for up to 10 years!