I bought this to power my paintball gun. As I don't plan on using my gun all that often I'm sure I would have to keep buying batteries so I bought a rechargeable. The fact that its ultra light is great as that shaves weight off my gun. I would say it weighs about half of what a normal alkaline battery weights. At this price, I highly recommended this.

I was excited about the USB rechargeable 9 volt battery, but it it is significantly wider than a standard sized 9 volt battery, so it won't fit in the devices that I could use it in. I contacted the company about the issue, but without a favorable outcome.

Both batteries only charged to 8.4 volts? 😒We shall see how long they last. My experience has been the rechargeable batteries charge a little higher than stated voltage. An one example example is *AA* rechargeable nicad batteries state that they are 1.2volts, with a fully charged maximum of 1.4volts. Most 3.7 lithium ion batteries top off at 4.2 volts on average. These supposed 9 volt batteries don't even reach their stated voltage metering out at 8.4 fully charged? Sending back for…

I love the concept of a 9v with a USB port. In practice, though, this one doesn't work. It charges to 8v (expected voltage with a LiIon), but won't hold the 8v more than a few minutes, then drops to 4v. I bought 3 and all exhibit the same problem.

Great battery, I use it to light up some lights and I’ve left it on by accident over night and it was still running the next morning. It’s worth the purchase. Just make sure you have a cable to charge it. It does not come with one. I used my PS4 controller cable to charge it.

The idea is really nice and I like the product.But it's slightly wider and slightly longer than regular battery.Basically it's plastic case seems to be exactly within the regular battery dimensions, but the transparent plastic heat shrink tube on top of it adds about 0.04"/1mm to width and height.I did read other comments about the dimensions before purchasing, but did not pay attention to it. Well, I still like it, but the size really matters. It turned out not to be as universal as I…

I bought this for my "tens" device (electric pulse system for treating back pain) - a fairly high current draw. A regular alkaline battery would last about 15 uses before losing charge. This device lasts about 3-4 uses before re-charging is required.Charges fast, though. Easy to do, with old-school USB micro-B cable.