I’ve written about many external battery packs that hold 9,000mAh or more, but I haven’t covered much in the sub-5000mAh area, and that’s a shame. If I’m going out for the evening, I’ll inevitably need a boost, but I won’t want to carry a bulky battery pack; that’s where the lipstick-sized Anker Astro Mini comes in. It’s evening bag friendly.
The kit includes the 3200mAh battery, a microUSB charging cable, and a cloth carrying case.
The Astro Mini is approximately 4″ long x 1″ wide, and it weighs2.9 ounces. I was sent the second generation version, which has 3200mAh — or enough to charge an iPhone 6 (which has an 1810mAh battery) about one and a half times and an iPhone 6 Plus (which has a 2915mAh battery) a bit more than one full charge from empty.
Needless to say, when you are going out and you’re carrying a tiny bag (or you don’t want to carry a bag at all), space is a premium. The Anker Astro Mini is small enough that it will fit in almost any evening bag or pocket, and carrying it will eliminate the evening’s dead battery fears. The only con I can come up with is that the battery doesn’t have a built-in or attached microUSB or Lightning cable, so you will want to invest in a small one that also packs well — something like the 4″ AmazonBasics Apple Certified Lightning to USB Cable 
One thing worth noting is that when I traveled to Detroit this week, SJT’s TSA rescanned my bag multiple times and then finally asked to dig around in it a bit. Of course I agreed, and the agent helping me finally said that it was because of “this” — holding up the Anker Astro Mini. I laughed and said it was a battery pack, and she said they had been trying to figure out if it was a flashlight or what. In any case, TSA was super friendly about it, and it wasn’t much of a hassle; leaving Detroit, the DTW TSA didn’t even look twice at it. =P
The Anker Astro Mini 3200 External Battery is available in blue, black, silver, pink, and gold; you can get yours at Amazon
[affiliate link].
Source: Manufacturer supplied review sample
What I Like: Extremely small, with enough mAh to charge your phone at least once from empty
What Needs Improvement: I truly wish these came with a choice of built-in short Lightning or microUSB cable