Monoprice Enhanced Active Noise Cancelling Earphones - Retail Packaging - Black Enjoy superb musical reproduction and noise cancelling with these Enhanced Active Noise Cancelling Earphones from Monoprice These earphones feature an inline active noise reduction (ANR) module, which helps eliminate up to 99% of external noise The ANR module is powered by a single AAA alkaline battery (included), which can provide up to 50 hours of active noise reduction