Walker's Slim Electronic Quad Electronic Earmuffs with Bluetooth - Ultra Low Profile Ear Cups. Bluetooth Sync with Mobile devices. Rubberized Coating. Four Hi Gain Omni Directional Microphones. Low Noise / Frequency tuned for natural sound clarity. Volume Control. Compact Folding Design. Comfort headband with metal wire frame. Sound dampening composite housing. NRR 23. Sound Activated Compression – 0.02 second reaction time. Recessed Volume Control Knob. External Battery Door. Operates on 2 “AAA” Ultra Low Profile Ear Cups Bluetooth Sync with Mobile devices Integrated Communication Mic Rubberized Coating Four Hi Gain Omni Directional Microphones Low Noise / Frequency tuned for natural sound clarity Volume Control Compact Folding Design Comfort headband with metal wire frame Sound dampening composite housing NRR 22 + Sound Activated Compression - 0.02 second reaction time Recessed Volume Control KnobExternal Battery Door Operates on 2 "AAA" batteries included