Walker's Ultimate Digital Quad Connect Muff with Bluetooth, Black 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