Koss UR40 Stereophone Titanium Sound in a Collapsible Lightweight Package The UR40 delivers digital quality sound in an ultra-lightweight design for listeners on-the-go. The UR40 features dynamic elements for a wide frequency response from 15-22,000 Hz. A 2 mil. titanium coating on its diaphragms increases the rigidity of the elements, minimizing mechanical distortion and ensuring exceedingly accurate sound reproduction. Computer-optimized neodymium iron boron rare earth magnet structures enable the UR40 to deliver greater volume, even with low-voltage portable devices. Oxygen-free copper voice coils improve signal transmission and conduction for cleaner, clearer sound. With its hybrid design, the UR40 combines the best of closed-style and open-style headphones. Closed leatherette earcushions form a light seal around the ears, enhancing bass frequencies. Screened earcups provide an open, hear-through sound that lets listeners stay in touch with the world around them. The result is a full frequency, clean sound that turns any recording into a "live" performance At just over six ounces the UR40 wears comfortably even after hours of continuous listening. The airy mesh sling provides soft breathable support, ideal for those with touch-sensitive scalps. An adjustable headband accommodates all head shapes and sizes for maximum comfort. When not in use, the resilient, lightweight frame folds into a compact configuration that's protective, easy to carry and convenient to store. Perfect for travel, the UR40 includes a straight dual-entry eight foot cord. A gold-flashed 3.5mm (1/8") plug, L-shaped to minimize cord stress is included. The UR40 will delight listeners seeking heavyweight sound in a comfortable lightweight package. Frequency Response 15-22,000 Hz Impedance 60 ohms Sensitivity 98 dB SPL/1mW Distortion <0.2% Cord Straight, Dual Entry, 8ft