I tried the ship’s headset at first but found the clarity to be terrible. As you will take the headset off at 18 K I didn’t want to spend the money for a Bose for example. It’s not a noisy Boeing after all. So I got myself a Telex Airman 850 ANR for about 400 $. I’m very happy to have it below 18K. And it doesn’t need so much space as an A20 in your flight kit.