How many sizes of soccer (football) balls are there?

American footballs come in two sizes: inflated and under-inflated.

As it's becoming clear that heading a football regularly is likely to cause brain problems later in life for players I'm surprised that that element of play is still allowed.

ElJavron619, did you mean inflated and Bradyball

ElJavron619, did not know this.Good info.

Besides being rarely seen in the US, what is size 2 used for? Seems the other sizes have all the bases covered