Communications & Ear Protection, Inc.
For those who prefer clarity when aloft but who prefer a lid to hopefully keep the bits that belong in the bonce where they belong, and bits that don't belong there out of it, should you be required to slam your noggin violently around the cockpit.
Far more effective than ANR in truly high-noise environments, and for a laughably small amount of dosh.
I must confess to being without my CEP earpieces at the moment, having lent them to a mate who lost the previous pair I lent him, when the CEP-equipped Russian helmet he was wearing fell over the side of his rice-burning Yak-imitation when he decided to stick his head out on landing without checking the chin-strap was done up. Naming no names....
Bob.