Spracht Konf-X Buds Noise Cancelling In-Ear Conference Call Headset with Built-In Microphone Active Noise Cancelling (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