3M Peltor Sport RangeGuard Electronic Hearing Protection NRR 21 dB - RG-OTH-4 Product OverviewPeltor Sport Range Guard Electronic Hearing Protector suppresses gunshot noise to protect hearing while amplifying voices for clear communication. Ideal for range and hunting use. Noise reduction rating (NRR) should be equal to 21dB. Low profile cup design works with shotguns and rifles. Single, external battery door. Adjustable padded headband. Durable recessed microphones. Single on/off and volume control. 4-hour auto shut off to preserve battery life. 3.5 mm audio input jack for MP3 and 2-way radio compatibility. Runs on 2AAA batteries (not included). NRR 21dBIdeal for both indoor and outdoor shooters and huntersSuppresses gunshot noise to protect hearing while amplifying voices for clear communicationLow profile cup design proven to work with shotguns and riflesRe-engineered headband for improved fit and comfort4-hour auto shut-offEasy-access battery door with tether (runs on 2 AAA batteries; not included)3.5 mm audio input jack compatible with most MP3 players and 2-way radiosDurable recessed microphonesProduct color is gray with black accents