The Sennheiser HD 490 Pro Professional Reference Studio Headphones are open-back, wired, circumaural headphones with a frequency range of 536 kHz. They have a 38 mm dynamic speaker driver, a max sound pressure level of 128 dBSPL, and an impedance of 130 ohms. The headphones weigh 260 grams without the cable and come with a 1.8 m detachable cable and 3.5 mm and quarter inch TRS jack adapters.