Walkers Razor Freedom Series Ear Muffs 23 dB NRR Black 2nd Amendment. 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. Specifications for Walkers Razor Freedom Series Ear Muffs: Manufacturer: Walkers Color: Black Fabric/Material: Polymer NRR: 23 dB Quantity: 1 Size: One Size Battery Type: AAA Battery Quantity: 2 Included Accessories: Standard Age Group: Adults Features of Walkers Razor Freedom Series Ear Muffs: Ultra Low-profile Ear Cups; Rubberized Coating; Two Hi Gain Omni Directional Microphones; Audio Input Jack; Low Noise / Frequency Tuned For Natural Sound Clarity; Volume Control; Compact Folding Design; Comfort Headband w/ Metal Wire Frame; Sound Dampening Composite Housing; Sound Activated Compression - 0.02 Second Reaction Time; Recessed Volume Control Knob External Battery Door Package Contents: Walkers Razor Freedom Series Ear Muffs (x2) AAA Batteries Walkers GWP-RSEMFS-2A: Razor Freedom Series Ear Muffs 23 dB NRR Black 2nd Amendment