(Update)
I've been using this for a couple of months and I think it's a little champion. I use it often and it has been running forever on the batteries I originally put in. I've even accidentally left it on over night a couple of times. This is a great little fan at a sweet little price.

I like this modest battery operated fan. The blades are narrow; they don't provide a strong air current. In other words, it's designed to use in close proximity. I set mine on my desk two feet away from my face. I especially like how quiet it is. It's lightweight (1 lb) and compact. It requires two D batteries (not included). There are two speeds. It doesn't have a power cord or a usb charging port. It's solely battery powered sans cords and its simplicity is what sold me. It's practical and it works. I'm glad I have it.

not worth the money - takes 2 "D" size batteries description says quiet which it is that but even with it sitting on my desk often I have to pick it up and see if it is still moving - no air to speak of - for the same price plus those huge batteries I have 2 others same size that will put some air movement in a small room, but will definitely cool you off if it is turned on and facing you. Eats D batteries like crazy - no place to hook up an AC adapter - even at that this thing really isn't sufficient air for a hamster cage, truly. ALSO very important, be careful. when I went to pick it up a couple of times to see if blades were even moving - the guard in front is so cheap and plastic, the blades hit it, just glad all it did was scare me. Not worth it to me to even return it. It is as the pictures Ive seen show of this one and others blowing a scarf or something, with this one at a foot and half away scarf doesn't move. Not being nasty just way not worth the money - not the hassle to return it. But I like lots of other stuff I buy.

The fan is pretty weak and the hinge between the base and fan was too tight. Felt like you almost had to break it to change the angle. Sure enough, fell off the window ledge and broke the first time I used it. Emailed the manufacturer directly and they haven't responded...it has now been a week. Either buy a beefier model, or spend a little more to find another brand.

Wish I could get a refund or at least a replacement, but I guess a fall is technically my fault, right? Who could have ever thought to design a portable cordless fan to withstand a 5 ft drop, right?!?

Let me start off by saying I purchased two fans with similar functions to test them side by side: the O2COOL and the OPOLAR F201 https://www.amazon.com/dp/B01DZYUL6A/ref=cm_sw_r_cp_awdb_gSodzbY5H1XAH

The O2COOL fan has one plus: it is adjustable so you can tilt it or stand it straight. Other than that, it's pretty unremarkable. It's made of cheap feeling plastic (I am aware that it's not a ridiculously expensive fan but, come on). It is battery operated, which wouldn't be that big of a deal if the batteries required weren't two D sized batteries. Not to mention, they're not even included with the fan. Who has those laying around?? So I bought the batteries (add another $5 to the price of this fan) and the fan power itself wasn't that impressive, even with those two big batteries. It has two speeds, low and high, and like I stated, not impressive simply ok. It's good if you don't want to worry about charging it (like for going camping) but other than that, it's just ok.

Now the OPOLAR F201 comes with a rechargeable battery and a USB cord to charge it. You don't have to worry about replacing batteries or running out to get some if you don't have the size it needs. It will last 3-7 hours with one charge depending on the speed you're using. It has 3 speeds and I found that even though it is smaller in size, it delivers more air than the O2COOL. It also has a very convenient LED light on the side that can be used as a flashlight if/when needed. It looks and feels like it's built with more quality materials. The only downside is that it's not adjustable so you can only stand it up in one position.

The OPOLAR F201 beat the O2COOL hands down. If I were to recommend a small, portable fan it would be the OPOLAR F201. I will leave the link here again https://www.amazon.com/dp/B01DZYUL6A/ref=cm_sw_r_cp_awdb_gSodzbY5H1XAH

I have been using a friend's fan that is exactly like this one, and it works well. However, when I received mine, it wouldn't work at all. I even tried replacing the batteries, even though I put brand new batteries in it. Then, I tried putting my friend's half used batteries in, just to make sure it wasn't a bad package of batteries I had received. No go. As I said, it works well, but be prepared to exchange it.