The Audio-Technica ATH-R70x Pro Reference Headphones are a professional grade, open-back reference design that feature specially designed 45mm drivers in acoustically transparent housings fashioned from aluminum honeycomb mesh to provide an accurate and natural open-back sound. The carbon composite resin in the design improves structural rigidity to provide a detailed transient response. High-efficiency magnets with a pure alloy magnetic circuit design helps reduce distortion and ensure an accurate and extended frequency response of 5 to 40,000 Hz.