Handy Cooler Small Fan & Mini-Air Conditioner: The Original in Blue. Portable and convenient. Runs on batteries or USB. Cools air up to 30F. The original patented hand held cooling fan as featured in Technology Review magazine (M.I.T.) in 2010. Small fan cools air up to 30F. *best used in hot and dry environments. Humidifies air and alleviates allergies. Runs on 4x batteries or USB power (adapter included). Cooling fan assembly utilizes a 30db whisper-soft turbine system. Cooling filter life expectancy: 1 year. Wash filter with soap and water before first use and occasionally during life of filter.