The Razor series feature 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 hunting partners, even when shots are being fired around you. This Razor Slim also comes with the Razor Walkie Talkie. The Walkie Talkie is custom designed to integrate on to the Razor Earmuff. It features 22 channels, a 2 to 3 mile range, and push to talk and voice activation. The Razor Walkie Talkie is a must-have accessory for your existing Razor Earmuffs. Your hearing cannot be replaced, so make sure you pick up a set of Walker's Razor Electronic Earmuffs with Free Walkie Talkie for your next trip to the woods or range.