It doesn't make absolute silence, more like the sounds are a bit duller and further away. I can confirm that it is very pleasant and you can work better. However, one should not expect that it will somehow become completely quiet around you. What's interesting is that when you turn it off, everything seems much louder.

Super headphones work very well, but it can be that you have the feeling afterwards that you were in a disco, depending on the ambient volume, because the technology is blasting your ears all the time, whether that is healthy, no one has ever asked...

Noises such as motors, fans, noise etc. are filtered very well. If someone is talking next to you, you can still hear it, but much quieter. Activate ANC and listen to quiet music and then you are pretty much in your own world. As has already been written, if you take the headphones off, everything seems much louder again.

I had the experience of flying for 12 hours and the reduction was great,
It also filters out the noise on the train.

I didn't buy it myself but a colleague tried it out and it's incredible. Absolute silence when switched on :)