Featuring Walker's New Line of the Freedom Series! This series has a Noise Reduction Rating (NRR) of 23 dB, and utilized sound activated compression (SAC) of 0.02 seconds. SAC is a special electronic circuitry that will compress gun shots and other loud noises down to a safe level, without completely shutting the noise off. This allows you to hear range commands or communicate with your shooting or hunting partners, even when shots are being fired around you. 23 dB Noise Reduction Rating Two Hi Gain Omni Directional Microphones Low Noise / Frequency tuned for natural sound clarity Sound Activated Compression 0.02 second reaction time Sound-dampening composite housing Rubberized Coating Ultra Low-Profile Ear Cups Comfort headband w/ metal wire frame Recessed Volume Control Knob Audio Input Jack External Battery Door Operates on 2 'AAA' batteries included