Batman replaced the traditional helmet that accompanies the Nomax Suit with his distinctive cowl, which does more than simply add to his daunting appearance.
Batman's cowl is sculpted from an impact-resistant, graphite-composite exterior. There is also bullet-proof Kevlar plating that shields sections of Batman's head and protects it from small-arms fire. Bundled into the "ears" of the cowl are high-gain microphones and a radio antenna. The radio antenna allows Batman to monitor police and emergency-services radio frequencies so that he can always be "first on the scene."
The microphones in the ears are combined with special earpieces in the cowl that give Batman superior hearing in the field. The microphones can also be used to amplify Batman's voice and broadcast it through a discreet speaker in the suit. This is what gives Batman's voice that distinctive, disembodied and unearthly sound.