Basically says that they can be used in practice but not games as they haven't been certified yet. Technically they are a helmet 'add on'. Here is an exact quote about it "Using a helmet add-on creates a new model of helmet, so an existing helmet certification, to the standard set by the National Operating Committee on Standards for Athletic Equipment, does not automatically apply.- If a helmet manufacturer certified a helmet with a helmet add-on, that could create an exception, but that hasn’t happened."