DESC: No matter where you go, enjoy peace and quiet with the MDR-NC22 noise canceling headphones. These compact and comfortable bud-style headphones can reduce noise by 75% (12dB at 200 Hz), and the 13.5mm driver units produce powerful sound. Perfect for tuning out noise at work, traveling, or even when you are trying to sleep in a loud environment. The noise canceling circuit actually senses outside noise with built-in microphones and sends an equal-but-opposite canceling signal to the headphones.