It is cold vapor fan to work through the system is Evaporative Cooling Systems or pulling the heat from the air through the sheets do cold. Which when exposed to water evaporation and changed into ice passed out. Easy Portable energy saving , water saving Because the water circulating in the system,maintenance .Cost less Disadvantages of Evaporative cooler must be filled with water to use it effectively. If used in a closed room for a long time may cause odor.Price cold vapor fan 2,000 bath.