Audio-Technica ATH-WS77 Solid Bass Over-Ear Headphones Newly developed Double Air Chamber System expands bass output for powerful bass without sacrificing audio clarity Large driver design (40 mm) reproduces outstanding sound Undesired vibrations are eliminated by direct-mounting the high-rigidity aluminum housing to the driver Acoustically sealed ear pads minimize bass sound leakage Smooth, easily adjustable headband slider ensures a comfortable fit