The Original American Stereophone Company ,Ever since we invented the world's first SP/3 stereophone back in 1958, Koss Stereophones have been bringing back the excitement of a live performance. Music lovers around the world recognize that dedication to accuracy in sound reproduction as The Sound of Koss. ,Key Features ,- Koss Touch Control (KTC) remote and microphone technology, made for iPhone®, iPad® and iPod® ,- Comfort Zone setting on temporal pad for comfortable, secure fit ,- The ultimate active headphones with a collapsible headband design for protective storage ,- Dynamic element for extended frequency response ,- Oxygen-free copper voice coils deliver deep bass and signal clarity ,- Includes a convenient carrying case for protective storage ,- Frequency Range: 15-25,000 Hz ,- Impedance: 60 Ω ,- Sensitivity: 101 dB SPL ,- Cable: Straight, Dual Entry, 4ft ,- Covered under the Koss Stereophones Limited Lifetime Warranty