I purchase this two power bank for me and my wife. 7800 mAh and two port USB port (5V/1A and 5V/2.1A)
MHa milli-ampere-hours. It's a measurement of the amount of energy the battery can store. The one with 3000 can store double the amount of energy that the one with 1500 can store. This does not translate directly into double the usage time for the device, but it is an indication on how long the device can power itself from the battery. 
I love the Power Bank, because I can have the freedom to stay outdoors without having the problem of having to find a power point. I hope I will not over charge my cell.
It is from china as you can see, there are grammar errors. Example on the number 2, two. Part...