Kool Down Evaporative Cooler, Black ULTIMATE FAN: The portable fan provides cooling relief that can cover a 49 sq. ft. area. This quiet fan provides two speed options and adjustable air vents for optimal comfort WATER COOL-OFF: Simply add cold water to the fans 28oz tank, and enjoy up to 10 hours of ultra-cooling action. Use the water level gauge to easily monitor the water level STAY POWERED: The standard model uses 4 C batteries (not included).