Active Noise Canceling (ANC) In Ear Headset blocks outside noise (up to 90%). 3 Mems Mics - including an In-Line Omni-Directional Microphone for High Audio Quality, Noise-X "Konf-Calls". Compatible with iOS, Android, BlackBerry or Windows phones. Still fully-functional without battery - Passive Mode. "Mon" button temporarily suspends the Noise Cancellation - So you can hear someone talking to you.