Code Red Battle Zero K2 Head Set. The Code Red Bone Conduction Headset doesn't block your ears allowing you to hear everything - even soft and muted voices - while transmitting and receiving audio directly from vocal vibrations in the skull. This lightweight tactical headset from Code Red can be used with bone conduction technology or with the traditional ear bud style. The bone conduction technology transmits and receives audio directly from vocal vibrations in the skull allowing the Code Red Battle Zero K2 Tactical Headset to be the preferred choice of many professionals. Package Contents: Code Red Battle Zero K2 Headset Code Red BattleZero-K2: Battle Zero K2 Head Set