This power bank is slim, and provides power to more than one mobile device — Windows or not.

Power banks are a great accessory to have on hand for any phone or tablet, especially when they grant the ability to push power to multiple devices. This particular power bank from Vinsic may not be the smallest portable battery on the market, but its sleek design looks sharp, and 2 USB ports are certainly better than one. Measuring a mere half-inch in thickness, you can slip it in a bag or carry-on without crowding it up. It's definitely too wide to store in your pocket though, which isn't ideal for a grab and go solution.

It's mostly made up of an aluminum alloy with plastic on the top and bottom. The top features 2 USB ports (2.1A and 1A), next to a single microUSB port used for charging the power bank. And yes, Vinsic includes a dainty 28-inch microUSB cable, but no charging block. To the left is the LED battery indicator that can always be checked by simply tapping the display. As soon as you plug in a device, it lights up immediately to show remaining battery life.

Since the Vinsic ultra-slim power bank packs an impressive 20000mAh, this thing can be a real life saver for any number of bad situations. While I would normally bring a couple backup batteries with me for some weekend camping, this one provides enough juice when fully charged to handle my Lumia 640 XL and my wife's Galaxy S6 — leaving plenty of life for additional boosts if needed. With 2 devices connected there doesn't seem to be a drop in charging speeds, which is sometimes the case with aftermarket power banks. For extra security, it also features over-charge, over-voltage, short circuit, and over-current protection for anything you end up plugging in.

Our take

The Vinsic 20000mAh ultra-slim power bank is a good accessory to bring with you for any lengthy trip. Its LED battery indicator is a cool addition next to having a couple USB ports for charging your devices simultaneously. Even though it seems to be built fairly well, I don't see this one surviving many spills without some kind of thin bumper. I'd also prefer it to be a bit more compact rather than just slim for the sake of pocketing. If you're interested in giving this one a try, it's available in dark grey (as pictured), pink, silver, and gold right now for $49.90 from Amazon.

Buy from Amazon ($49.90)