Ultra Low Profile Ear Cups. Bluetooth Sync with Mobile devices. Four Hi Gain Omni Directional Microphones. Low Noise / Frequency tuned for natural sound clarity. Comfort headband w/ metal wire frame. Sound dampening composite housing. Sound Activated Compression – 0.02 second reaction time. Recessed Volume Control KnobExternal Battery Door. Operates on 2 “AAA” batteries included.