I am also using the Iphone Wall charger. Specifically, I'm using the official wall adapter that comes with the Iphone.
And actually, the ratings for the charger ARE on it, their just REALLY hard to read.
RavenII is correct. 5v at 1A.
I'm currently using mine, and it works GREAT! My vapor is warmer, And i get better throat hits using it versus using my PC, or using a wall to USB adapter that only pumps out .5A
I have yet to have any problems, No burned out Atomizers or anything.