Eva-Dry Renewable Wireless High Capacity Dehumidifiers E-500 (2) Sold in Two Pack- Indicator window with special " color changing crystals" that change from blue (when dry) to pink (when wet) to indicate when the unit needs to be "renewed" Absorbs 6-8 ounces of moisture Works in a 500 cubic ft area No batteries or cords required * 100% renewable - works up to 10 years * Compact and silent * Spill and mess free * Non-toxic, child and pet safe * Eco-Friendly