Peltor Sport RangeGuard Electronic Hearing Protector is ideal for range and hunting use. It suppresses gunshot noise to protect hearing with a noise reduction rating NRR equal to 21 dB while amplifying voices for clear communication. It has an adjustable padded headband and its low profile cup design works with shotguns and rifles. The RangeGuard features durable recessed microphones with single onoff and volume control and a 3.5 mm audio input jack for mp3 and 2way radio compatibility. It runs on 2 AAA batteries not included accessed by a single external battery door and 4hour auto shut off to preserve battery life.