Fangrui Product Details Enery-saving Eco-friendly - This Evaporative Air Cooler Is Freon-free Do Not Contain Refrigerant And Eco-friendly, Low Energy Consumption Same As The Power Consumption Of A Light Bulb, Uses Much Cheaper Than Running A Freon Air Conditioner In Hot Summer Days. Its Power Is Supplied By The Usb Port, One Refill Of Water Can Last About 8 Hours; You Can Use This Personal Air Cooler All Night Without Concern About Your Bills Large Capacity Water Tank - This Small Air Cooler With A Large 500 Milliliters Water Tank, Add And Water To The Water Tank, Cold Air Can Be Sprayed Continuously For 2-3 Hours To Keep Your Body Cool At Night For A Good Sleep. Also, The Water Shortage Protection Function Change It To Natural Wind While The Water Out, So No Worries When You Fall Asleep. Outperformed Most Of The Regular Fan On The Market When Cooling Down Portable Easy To Use - With A Portable And Compact Design, This Usb Air Cooler Can Be Easily Moved From Room To Room, You Can Place The Evaporative Cooler In Your Kitchen,