Walker's Razor Quad Electronic Earmuffs - Ultra Low Profile Ear Cups 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” batteries included. Ultra Low Profile Ear Cups 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" batteries included