Power: It operates on 2 AAA batteries included Headband: It features a comfortable headband with a metal wire frame Noise Reduction Rating: This series has a Noise Reduction Rating (NRR) of 23 dB Compact: It features a compact folding design making it easy to store and travel with Sound Activated Compression: 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