With its unique D-Profile design and precision tuned sound, the Koss UR23i Full Size Headphone is ideal for personal listening. Isolation from ultra soft cushions and closed back design brings you closer to the music. Durable lightweight design makes the Koss UR23i a great portable headphone for traveling. Answer calls, play, pause, or skip tracks with the UR23i's in-line one touch microphone Specifications: Frequency Range: 20 - 20,000 Hz, Impedantion: 34 Ohms, Sensitivity: 94 dB SPL, Straight, Dual Entry, 4ft w/ 3.5mm Plug. Finish: Green