5V/1.2A Portable Power Bank VS iphone5

[loy.noppadol]

Is there any problem if i use portable power bank which have 5V 1.2A output to charge my iphone5. I just buy the 7800 mAh power bank with 2 outputs 5V/1.2A and 5V/2.1A. The shop told that first one for iphone, the second for ipad. Once i was home i just saw at iphone charger, It use 5V/1A deliver electicity to iphone.

By using the power bank, Is there any effect for iphone battery?