Radians Pro-Amp earmuffs NRR 23 rating Meets or exceeds ANSI S3.19-1974 standards 2 high-frequency, forward-facing microphones Independent volume controls for each muff Hearing protection for impulse sounds Compresses harmful noise to below 85dB Sound amplification to clearly hear conversation Adjustable CoolMax headband wicks away moisture Collapses for easy storage Includes 6 AAA batteries (3 for each muff) & a set of replacement microphone covers Approx. 280 hrs of battery life