Eva-dry E-500 Renewable Reusable Mini DehumidifierEnvironmentally Safe No Messy Spills or Refills to buy EVER! 10 year life span! Brand NEW design Completely silent when operating How It Works: The E 500 uses a renewable silica gel technology that works without batteries or power. This renewable solution can be placed in any area up to 500 cubic feet and will silently absorb moisture. As the unit absorbs the humidity there is an indicator window that contains crystals that will change from Orange to