Review on 🔋 O2COOL Treva Portable Battery Operated Fan - 10 Inch Blades - Smart Power Air Circulator for Camping, Travel, and Indoors Use - Includes AC Adapter, Rechargeable Batteries, and USB Charging Port by Wayne Flores

, I have an old 02 fan that runs on 8 D batteries and used it during Hurricane Irma. It worked fine. Having had another fan for several years, I decided to buy another fan in case the first one died. The new one I bought also runs on 8 D batteries, has a built in rechargeable battery and a USB port to charge your devices. Haven't used it yet but tested as best I could. The battery works like USB. There are 2 compartments for type D batteries - each with 4 batteries. However, D-cell batteries are extremely difficult to insert and remove - a very tight fit. If you know a storm is coming, you need to prepare the batteries in advance or you might give up. It took me at least 5 or 6 minutes to get in and then about 4 minutes to get them out. The fan uses the best battery source first so I don't know if D batteries will work and didn't want to try swapping batteries out for other D batteries as it was difficult to get batteries in and out. I will risk it. I can't comment on the cool 02 fans that only use 6-cell D batteries, but I didn't buy them as reviews showed these models lacked power. The new one seems strong enough, but I only gave it 3 stars because it was difficult to insert/remove the batteries and I couldn't fully test the fan.