QuietOn with ANC technology makes a big difference at low frequencies, such as the hum of airplane engines, construction sites or normal background noise. Its attenuation ability in this area is up to 40dB. For instance, airplane cabin noise sounds like a faint hum with QuietOn earplugs. It, therefore, significantly reduces stress level caused by constantly noisy environments. In mid and high frequencies, QuietOn’s noise cancelling is as good as foam earplugs’.