The most important thing to remember about Plugfones is that they're earplugs first and earbuds second. As such, the entire Plugfones line is tested and compliant with ANSI S3.19-1974 noise reduction standards and meets NIOSH criteria. When used as directed, our products are certified for Noise Reduction Ratings (NRR) of 23 or 26 dB, depending on the plugs used. For environments with high levels of noise, it may be necessary to use over ear protection such as earmuffs in conjunction with Plugfones products.