Audio-Technica ATH-ANC33iS QuietPoint? Active Noise-Cancelling In-Ear Headphones reduce distracting background noise by up to 90% while offering the superior sound. Electronics in the QuietPoint control module create a noise-cancelling wave that is 180? out of phase with the ambient noise. This wave acts like a noise eraser: it cancels out the annoying sounds that surround you without diminishing the audio you want to hear. The result... a peaceful enclave to enjoy the music or movies of your choice. The ATH-ANC33iS in-ear headphones also feature an inline microphone and controller for answering calls and controlling music. The mic and controller support smartphones， iPhones， iPads， many iPods & other compatible devices.