I found HS748s were painfully noisy! A guaranteed headache on a 6 sector day! ANR headsets were a lifesaver! They try and cancel out the ambient noise passing through the headset. In practice, they reduce ambient noise reaching the wearer's ears by a large proportion. The effect is noticeable when you look at the volume setting you have with and without an ANT headset. Without, it can be nearly full volume, with- less than half.