The Koss UR40 combines powerful sound with an ultralight design, optimal when you want to enjoy your music on the go. With improved signal transmission for a clean and clear sound, these headphones will minimize mechanical distortion and ensure extremely accurate sound reproduction. With a hybrid design, the UR40 integrates the best of surround and open headphones. Wrap-around leatherette ear cushions form a seal around the ears to enhance bass frequency, while perforated earcups deliver open, audible ambient sound that keeps you aware of your surroundings. The result: a fantastic sound that turns every recording into a "live" performance. With just over 170 grams, you can wear the Koss UR40 headphones comfortably, store them easily and travel easily. Titanium sound in a foldable, lightweight package. Specifications Frequency response: 15-22,000 Hz Impedance: 60 ohms Sensitivity: 98 dB SPL / 1mW Plug: 3.5 mm Weight: 170 g Headphone suitable for both computer and portable devices; Titanium diaphragm for crystal clear sound; Collapsible for ease of use transport