Radians 430-ehp black and the 430-ehp4u camo are electronic sound amplification earmuffs.One independent microphone picks up and amplifies low sound level noises.They have a compact folding feature for easy storage.When sound levels exceed 85db, the electronic circuit automatically protects at nrr 26.These muffs also amplifies sound while they protect hearing.They also feature an on/off volume control, padded headband and a battery life of about 200 hours.Type: ElectronicColor: Camo Ear Cups w/Black BandNrr: 27 dBQuantity: 1 PairStyle: Over the Head