The Audio Technica ATH-AD900X Audiophile Open-Air Headphones feature an open back design and 53mm drivers with rare-earth magnets that were designed by Audio Technica solely for the headphones. They have copper-clad aluminum-wire voice coils and a 5Hz to 35kHz frequency response for accurate audio reproduction. They also feature cushioned earpads with honeycomb aluminum casing and Audio Technica's 3D Wing Support Housing for adjustable wear. The ATH-AD900Xs have a three-meter cable that terminates with a gold-plated 1/8" mini-stereo connector. A detachable 1/4" adapter is included.