title: Dual protection.
authors.affiliation: E.A.R, Indianapolis, Ind., USA.
authors.forename: E H
authors.initials: EH
authors.lastname: Berger
mesh_terms: D004430:Ear Protective Devices / Q000706:statistics & numerical data; D006801:Humans; D009623:Noise, Occupational / Q000517:prevention & control*; D016273:Occupational Exposure / Q000517:prevention & control