QUESTION: What is meant by Noise Reduction Rating? ANSWER: That is the number of decibels by which the hearing protector will reduce the noise. For example, if you are working in an environment with a noise level of 90 dB, a protector with 28 dB NNR (Noise Reduction Rating) will reduce the noise 28 decibels. Scientifically that is a lot more than it appears, because every time you reduce noise levels by three decibels it is like cutting it in half.
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