Purely examples, I went two days with 2 iPhones and Samsung Galaxy TAB 3 weekend tablet: the battery allowed to recharge these 3 devices without difficulty during my stay.
The battery is fully recharged in 6 hours but charging an iPhone in 2 hours for 7.5% of the battery capacity. This is the tablet for a little longer: it takes 3:30 at the rate of 30% per hour of charging capacity. A bit tight for 3 unit of 2 days, but it gave me enough reserves to keep all this time Battery 1-port USB 1 Amp 1 and Amp 2 to meet any situation.
Personally, I do a lot of driving and it is possible to charge this battery with the adapter OXA® 5V / 4.2A dual USB output: car charger plugs into the car lallume cigars.
Really, this OXA gives me satisfaction and I can only recommend it to those who, like me, need to have always a solution to recharge their dune far socket devices.
The fact that this battery, which is not always the case with external batteries, equally bear the Apple product and other brands is a major asset for this type of product.
I highly recommend all the more that its cost is relatively low for the service rendered by this battery at OXA. It will soon become indispensable for you.