Porta Pro On-Ear Headphones Koss Porta Pro headphones’ high quality sound set sound performance and comfort standards for portable personal listening worldwide when first introduced in 1984. Since then, to the delight of devout Porta Pro enthusiasts, Koss has preserved the original design and performance that made the Porta Pro a portable music icon. Designed for those with refined musical taste, the lightweight Koss Porta Pro headphones continue to be the most requested headphone on koss.com. Constructed from Mylar, the elements are extremely rigid, minimizing mechanical distortion and ensuring exceedingly accurate sound reproduction. Koss Porta Pros feature dynamic elements that deliver exceptionally rich, deep bass, and a remarkably wide frequency response to capture every nuance in your favorite movie or musical performance. Features: The ultra portable on-ear headphones 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 Covered under the Koss Stereophones Limited Lifetime Warranty Specifications: Frequency Response 15-25,000 Hz Impedance 60 ohms Sensitivity 101 dB SPL/1mW Cord Straight, Dual Entry, 4ft