the very best portable power bank
This little thing is simply awesome and this is why;
Unlike many power banks out there promising to charge your phone twice (even thrice), this one actually lives up to the promise. It manages to charge my iPhone 6s almost twice. I believe the promise is 1.5x but the Anker Astro E1, with it's 5200 mAh of juice, has got my phone to 1.8x at one point.
It's so small it fits into any pocket. I usually pop it into the same pocket as my phone, with the charging cable connected. Though light weight, it has a solid, high quality feel to it. The proprietary PowerIQ technology means it charges compatible devices like iPhones very quickly indeed. Most of the latest Android phones will also charge very quickly with this tech.
The one things that may annoy some is the glossy piano-black finish which attracts a lot of fingerprints. However it has a fabric pouch that prevents this. I normally prefer a matte finish, and would have enjoyed this product more had it been matte, but it's not a deal-breaker.
Here are the Amazon (affiliate) links to the product if you want one.
Anker Astro E1: US
Anker Astro E1: UK
I made the following video about it if you're interested.