2015 new! COOLUP Slim One 3500mAh Air Portable Charger external battery charger Power Bank (only 4.5mm, Unibody Aluminum Housing), for iPhone 6 Plus 5s 5c 5 4S (Apple adapters not included), Samsung Galaxy S5 S4 S3 Note 3, 4, LG Volt G3 Optimus Realm, Nexus 4 6, HTC One M8 M7 Desire 816 and Other Smartphones (Blue)

This is the best slim charger, I can put this in my bag and keep it moving.

Only used it once to top off my battery went from 49% to about 79% in about a half hour. Looked like it used half the power in the charger but I will see. sometime batteries get better as they get older. Only thing is that I wish I would have Gorton the red color.

Horrible product! Do they buy! Looks nice but would not hold a charge. Would not charge iPhone 6 either. Weird hookup piece added to the order to try and make it work. Awful!

I've not had to use it very often - but so far, so good ! the size is great and it comes in a little slotted-wallet style case.

Not sure how it works....I charged it up but when I went to use..... I don't have the right core that will charge my phone I use your charger that I already had but whatever supposed to plug into the charger and plug into the phone I don't have it so this is a waste of money! Doesn't have a normal outlets so I have no attachment to be able to use this big big big waste of money!

Awful charger. Never even worked when I got it.

Your browser does not support HTML5 video.  (I received a free sample for an evaluation and honest review.)The video shows off both the 2000 and 3500mAh versions of COOLUP's Slim One line. They both come with all required accessories (except for an AC charger, but most battery packs don't come with one), and they also come with little wallets to carry the pack and cash/cards/whatever.The name should give this away :), but these are incredibly thin for a battery pack. It's one thing to see it in a photo, but it really did impress me once I had them in hand. I have other "thin" packs (one of which I show in the video), but these just blow them away in terms of size. Very impressive. The awesome form factor and how they still included standard features are the reasons for me giving this five stars.The product description as I write this states that these have a unibody aluminum housing - they do not. At least the black version doesn't. The top and bottom lids are plastic as far as I can tell. I actually prefer the plastic, but I wanted to note it in case you specifically want a metal case.The thin nature of them does lead to limitations. First, the capacity. These definitely aren't the highest capacity on the market, and with the current pricing (this 3500mAh version is listed at $30), they aren't the biggest mAh/buck out there. Also, a regular USB port won't fit, so they a single input/output micro USB charging port. Personally, I'm not always interested in the highest capacity for the price - I'm willing to pay extra for a nice metal case or a form factor that I like, and I really like this form factor. In regards to not having a full-size USB port, these come with the proper cable to use with them, as well as two adapters to make it easy for you to use other cables if you want. Because I need to pack along a cable with me when I bring my other battery packs, it's no inconvenience to me to bring this cable instead. The only hitch will be if you forget it, as your friends/family will probably have spare charging cables that use a regular USB plug.The wallet that comes with this 3500mAh version is actually pretty useful. It has a slot for the battery that completely contains it, and it also has areas for credit cards, ID, and cash. I'll probably never use it because I don't need a battery in with my cash, but it is pretty nice.Charging output is listed at 1A, and input at 800mA. Not the fastest on the market, but definitely in line with other smaller battery packs. It also has standard indicator lights showing the level of charge remaining (four lights).The only thing that I don't really like about the one that I got is that one of the lids is a little loose. It doesn't rattle around or anything, mind you, but it will slide back and forth ever so slightly - and that makes it feel loose and reduces the sense of quality in the pack.Overall, given all of the nice qualities of it - especially the amazing thinness - I think these are worthy of five stars. At the current price, I'd definitely say only get one if you really want the slim factor, as there are other fairly small packs that hold more and cost less. If you want slim, though, these are an excellent choice.