Engineered to create a comfortable listening environment in areas with high ambient noise, these in-ear earphone 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 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 is a peaceful enclave to enjoy the music or movies of your choice.