Equiped with Ice-pak,Ice-Tubes.Highly efficient cold -retention medium. Once frozen ,these cold-retention modules could last several hours. No need to use alternative air cooling/drying elements,By using both modules ,the air is already cooler and drier. This fan can produce warm wind in the cold wind.And at the same time you can also choose its humidifying function as u wish. Equipped with negative ions,it is helpful in killing bacteria and virus.