Honeywell Impact Pro Sound Amplification Electronic Earmuffs were designed for handgun and pistol shooters looking for maximum hearing protection. These earmuffs carry a Noise Reduction Rating (NRR) of 30 in both on and off mode. When the electronic ear protection is switched on, these earmuffs employ built-in directional microphones that amplify range commands and other ambient sounds to a safe 82 dB, providing more natural listening and enhanced communication. As an added safety feature, Honeywell Earmuffs also actively listen and automatically shut off amplification when loud impulsive sounds like firearm discharges reach 82 dB. Padded headband features telescopic height adjustment for a comfortable, customized fit. Rubberized pressure points prevent gunstock scratching. An external audio jack lets you connect the earmuffs to an MP3 player, scanner or other audio source. The automatic shut-off function after 4 hours helps extend battery life. Protect yourself against hazardous gunfire noise without being left in silence.