ATH-ANC23 QuietPoint Active Noise-Cancelling In-Ear Headphones reduce distracting background noise by up to 90% while offering the superior sound. Engineered to create a comfortable listening environment in areas with high ambient noise, these in-ear headphones feature a miniature microphone in each earpiece that picks up ambient noise (such as traffic, air-handling systems, etc.). Electronics in the control box create a noise-cancelling wave that is 180deg. 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.