You are just tired: Your Brand new mobile phone cannot even stay alive 1 day! you had a look on the internet and you want to by a power Bank… Great, you found the solution!
But (There is always a but) you do not know which capacity you need… 2200 mAh, 2600 mAh, 5200 mAh…
The reply is very easy: just open your mobile phone cover (Except if you earn an Iphone) and have a look at your Battery power: You will find the required capacity of your mobile phone.
Most of Mobile Phones (I Phone inclusive) request a 2200 mAh at least to charge your phone 100%.
If you buy less than 2200 mAh , your mobile phone will not be charged 100% by the power Bank.
If you buy more than 2200 mAh, you will be able to charge several time your Mobile Phone.
Easy right?
Be also be sure that in the future the capacity of your Battery will be bigger and bigger!

Power bank is a great promotionnal Item, according to our experience, the best deal in 2014 was the 2200 mAh, in 2015, consider 4400 Mah
Hope this helps in your choice!