Philips HN 110 Folding Noise-Canceling Headphones (Discontinued by Manufacturer) Noise canceling feature reduces background nose in any environment; ideal for airplane, train and bus use Closed-style, dynamic headphone with 40mm driver, neodymium magnet, and CCAW voice coils Foldable headband allows phones to fold down to a small size for convenient storage when not in use Includes 1/4-inch adapter, in-flight adapter, battery for active electronics, carrying pouch Frequency response: 20Hz20kHz; noise attenuation: 50-1,500Hz, &gt;10dB at 300Hz