NRR = not really relevant?
Hager
Lee D
LD
Sonomax, Montreal, Canada. leehager@cablespeed.com
D004430:Ear Protective Devices / Q000592:standards*; D006317:Hearing Loss, Noise-Induced / Q000517:prevention & control*; D006801:Humans; D009784:Occupational Diseases / Q000517:prevention & control*; D014481:United States; D014484:United States Environmental Protection Agency; D014489:United States Occupational Safety and Health Administration