3M Peltor H6A\V Optime 95 Over the Head Noise Reduction Earmuff, Hearing Protection, Ear Protectors, NRR 21dB, Ideal for machine shops and power tools Noise Reduction Rating of 21 dB Recommended for noise levels up to 95 dBA CSA Class A Twin cup design minimizes resonance Twin cup design achieves the maximum high and low frequency attenuation Peltor part H6A\V