The Razor XTRM series features cooling headband, Noise Reduction Rating (NRR) of 21 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. Your hearing cannot be replaced, so make sure you pick up a set of Walker's Razor Electronic Earmuffs for your next trip to the woods or range. Includes 2 AAA batteries.FeaturesAdvanced digital circuitActive dynamic sound suppressionHu-gain omnidirectional microphonesDynamic wind noise reductionSuperior clear digital soundPremium cooling headbandGel-filled ear pads for cooling and comfortAudio input jackRecessed volume control knobsNRR - 21dbBattery - 2 'AAA' batteriesApp supported - no