Compatible with Plugfones Bluetooth and Wired headphones, these replacement ear plugs are tested and compliant with ANSI S3.19-1974 noise reduction standards and meets NIOSH criteria. When used as directed, our ComforTwist Foam Plugs are certified for a Noise Reduction Rating (NRR) of 23 dB. For environments with high levels of noise, it may be necessary to use a volume limiter in conjunction with Plugfones products.