Peltor Sport RangeGuard 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) equal to 21 decibels. Low profile cup design works with shotguns & 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. 3.5mm audio input jack for MP3 & 2 way radio compatibility. Runs on 2AAA batteries (not included).NRR: 21 dB noise reduction ratingIDEAL FOR both indoor and outdoor shooters and huntersSUPPRESSES gunshot noise to protect hearing while amplifying voices for clear communicationDURABLE RECESSED MICROPHONES prevent damage and reduce wind noiseLOW-PROFILE CUPS with cut-outs designed for rifle and shotgun useADJUSTABLE HEADBAND for a comfortable fitRUNS ON 2 AAA BATTERIES (not included)3.5 mm audio input jack compatible with most MP3 players and 2-way radiosDurable recessed microphones