Noise Reduction Rating (NRR) is a unit of measurement used to determine the effectiveness of hearing protection devices to decrease sound exposure within a given working environment. Classified by their potential to reduce noise in decibels (dB), a term used to categorise the power or density of sound.
Hearing protectors must be tested and approved in the USA by the American National Standards (ANSI) and CE certified in Europe. Snugs GO Shield is rated at 26 dB NRR and is accredited to test to ANSI S3. 19-1974, ANSI S12.6-2016, ANSI S12.42-2010, EN352 parts 1-8 and AS/NZ S1270:2002 by the National Institute of Standards and Technology (NIST) National Voluntary Laboratory Accreditation Program (NVLAP).
The higher the NRR number in the USA (or SNR in Europe) associated with a hearing protector the greater the potential for noise reduction.