I forget what brand it is, but my current helmet has a bee guard on it -- a mesh screen behind the vents. It seemed like a brilliant idea to me because I am always getting bees in my helmet and they scare the bejeezus out of me.

Last time I wore it, a bee flew in the side, where there is no mesh. And then couldn't get out the front because of the mesh.

So I am thinking this is a dumb feature.