This evaporative cooler (more colorfully known as a "swamp cooler) is like a portable air conditioner! It can cool the air up to 30 degrees Fahrenheit by through the cool science of phase transition in water. Air is forced across the dampened cooling 'filter' by the fan to produce a cooling effect that works similarly to a mist fan but without spraying unevaporated water particles all over the place. You can use it indoors or outside and can be powered by 4AA batteries or USB! You will now have one less reason to bark during the dog days of summer!