Walker's Ultimate Digital Quad Connect Muffs with Bluetooth. Bluetooth Sync with Mobile devices. Integrated Communication Mic. Four Hi Gain Omni Directional Microphones. Low Noise / Frequency tuned for natural sound clarity. Independent Volume Control. Independent Adjustable Frequency Tuning. Compact Folding Design. Comfort headband w/ metal wire frame. Sound dampening composite housing. NRR 24dB. Sound Activated Compression - 0.02 second reaction time. Low Profile Ear Cups. Recessed Volume / AFT Control Knobs. External Battery Door. Operates on 2 "AAA" batteries included.