When the battery in your phone isn't good enough, there's a plethora of external batteries available to pick up the slack. The ReVIVE ReStore Q10x is a 10,000mAh unit that usually costs about $35, but it's on sale at just $19.99 for the next few days. It's available with Amazon Prime shipping too.

Amazon.com_ ReVIVE ReStore Q10x Rechargeable 10,000mAh USB Power Bank Battery Pa

The Q10x has two USB ports with 1A and 2.1A output, as well as an LED flashlight to help get things plugged in at night. There's also an LCD display that keeps you updated on the battery level.

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$19.99 is a good price for 10,000mAh. These batteries are usually a few bucks more even when they're on sale. You can snag this deal until Saturday (2/14), at which point the price will go back up.