Airbition 10000mAh Rechargeable Clip on Fan - 8-Inch Portable USB Desk Fan with Strong Clamp for Golf Cart, RV, Car, Camping Tent, Treadmill Workout & Office Use - Battery Operated Personal Cooling Fan for Travel, Bedside & Workspace

I was going to absolutely rave about this fan until it unexpectedly ran out of battery on my mail delivery route at work. I had the fan on High for about 4 and a half hours which isn't even the highest setting. It was claimed to last 8 hours by the manufacturer. That would even be ok with me since it's the most powerful and effective USB clip-on fan I've ever used. What really upset me is that when charging and using the fan at the same time, you can only use Low and Medium speeds. It's inexcusable to me that you can't at least use the High setting, which is by far the most effective and efficient speed IMO. Medium does not cut it on hot days. So you are stuck with an underpowered fan if you run out of battery and don't have access to an electrical plug.Other than that major letdown it's simply the best fan if you are a delivery driver inside of hot trucks with poor air ventilation and no AC. The clip is strong and surprisingly versatile to clip even in pretty small tight spaces. Even the low setting works well in cool conditions and is unbelievably quiet to the point you can hardly tell it's on, if it weren't for the breeze. The difference between Medium and High is huge in air flow and volume. But it's still not an irritating loud at all. The ultra high setting is simply pointless IMO because it will drain the battery in 2 hours or less. Should only be used for a quick cool down but it is impressive for an 8 inch fan. The only negative thing other than the overstated battery life is that this fan seems to do worse than most fans in outdoor settings in windy conditions.The fact that I'm still rating this fan 4 stars despite my disappointment with the battery issues should tell you how much I like this fan. These issues may be non-factors if you don't use fans for lengthy periods on high settings.Update: 7/16/2023Found out you are only limited on fan speed while charging when the battery is very low. Which makes sense if there is not enough power to run the fan while low on charge. So at least you can get some extra time from the fan if you have it hooked up to a power bank with the fan charged. However it is not recommended to charge while using very often because it can weaken the battery prematurely over time. Also found out the manufacturer said 6 Hours on High and not 8 like I thought I remember seeing. So turns out their claims were within 1 hour of the times I experienced. So not too bad after all. I only wish the fan lasted a bit longer on the high setting. Which is the best setting for hot days IMO.