The most important thing to remember about Plugfones ComforTwist Foam Replacement Earplugs is that they are earplugs first and earbuds second. As such, these foam earplugs has been tested and compliant with ANSI S3.19-1974 noise reduction standards and meets NIOSH criteria with a noise reduction rating of 23 dB. Note: For environments with high levels of noise, it may be necessary to use over ear protection such as earmuffs in conjunction with Plugfones products.