The Remington 500 Mini Dehumidifier absorbs excess moisture. No messy spills or refills. No batteries or wires required. 100% re-newable...nothing extra to purchase. --How it works: The Remington Model 500 unit contains Water Glass Technlogy crystals. Water Glass is a very thirsty substance. In fact, it has an absorption rate much higher than traditional, soluble humidity absorbing products. It is colorless, odorless and non-toxic. Water Glass Technology is the most efficient way to absorb moisture. --INDICATOR WINDOW BLUE: The dehumidifier is ready for use; simply sit in desired location. The 500 will absorb excess moisture until the indicator changes to PINK. When indicator is PINK, plug the unit into an electrical outlet in a well ventilated area. Leave plugged in until the indicator changes to BLUE (usually 8 to 12 hours). The 500 is now like new and ready to absorb moisture again. Usefull for file cabinets, camera rooms, firearms, knives, RV's, boats, closets, safes or anywhere a compact dehumidifer is needed. Approx 6" high, 7 3/4" wide and 3 1/4" thick. Simple....effective....so protect your guns, knives, clothing and other valuables with this compact dehumidifer.