A:Answer Hello Vanny, thank you for asking about the QuietComfort 35 wireless headphones. These headphones do not have a specific button for the noise-cancellation. If the headphones are charged and powered on, the noise-cancellation will automatically be turned on. To turn off the noise-cancellation, you will want to turn off the headphones. Please note that turning off the headphones or inserting the optional audio cable will disable Bluetooth. Hope this helps! Josselyn - Bose Support