These Sony MDR-7502 closed ear headphones have a 30mm driver unit for clear, high quality sound reproduction. Includes stereo unimatch plug for use in 1/4 inch and 1/8 inch applications. Response is 60-16k and the impedance is 24 ohms. Headphone features include: 30mm driver unit, closed ear design, gold connectors and oxygen free cord, frequency response (60Hz to 16kHz).