Silicone Ear Tips - Attenuation Data (ANSI S3.19-1974) Test Frequency (Hz) 125 250 500 1000 2000 3150 4000 6300 8000 Mean Attenuation (dB) 28.3 24.3 25.7 28.0 29.3 31.3 35.3 41.0 48.7 Standard Deviation 2.9 2.5 3.5 3.1 2.1 1.5 1.0 0.6 1.5 NRR 25 Foam Ear Tips - Attenuation Data (ANSI S3.19-1974) Test Frequency (Hz) 125 250 500 1000 2000 3150 4000 6300 8000 Mean Attenuation (dB) 19.3 22.3 22.3 27.3 30.7 33.0 39.3 42.0 48.7 Standard Deviation 0.6 3.1 1.2 0.6 1.