Noise canceling headsets and headphones designed for listening tasks use a combination of passive soundproofing and type of technology called active noise control to reduce exposure to unwanted background noise and improve the signal to noise ration when listening to music or another sound source through the headset. Headphones and headsets of this type usually have a small battery door built into one of the ear cups.
When purchasing a noise canceling headset, be sure that you are purchasing the correct type for the task at hand. Some headsets that are advertised as having noise canceling microphones are intended for speaking rather than listening tasks. These only have noise cancellation in the microphone portion of the headset and do not have a battery on the ear cup.