One thing about helmets is how hot they can get, when you have been batting for a while on a summer afternoon. What if I wanted just a grille arrangement that encompassed my whole head, not just the bit in front of my face. It could be attached to a stiff headband of some sort, adjustable to the right size and with a chin strap, but did away with the traditional 'helmet' bit. Might look a bit weird at first glance, but it would be light and cool, with good visibility, and probably protective enough if done properly.