I have an AFX17 black/white/silver multi helmet, as far as the sizing chart goes forget about it - it is way off. According to the chart I should wearing a large, but the one that actually fits is a 3XL. Couldn't even get a XL on. The 2XL folded the tips of my ears down.
As far as the amble ear cavities for speakers. Tried to put Motocomm speakers in it and they were covered up by the liner and set behind the ear. Combination of which made it impossible to hear while going down the trail.