Bluetooth Sync with Mobile devices with Integrated Communication Mic, Four Hi Gain Omni Directional Microphones with Low Noise/Frequency tuned for natural sound clarity. Independent Volume Control and Independent Adjustable Frequency Tuning. Compact Folding Design, Comfort headband w/metal wire frame and Low Profile Ear Cups. Sound dampening composite housing, NRR 27dB and Sound Activated Compression - 0.02 second reaction time. Recessed Volume/AFT Control Knobs, External Battery Door and Operates on 2 "AAA" batteries included.