Koss UR40 Collapsible Over-Ear Headphones Hybrid Design Combines The Best Of Closed-Style and Open-Style Headphones. Connectivity Technology: Wired Closed Leatherette Ear Cushions Form A Light Seal Around The Ears Screened Ear Cups Provide An Open, Hear-Through Sound Adjustable Headband Accommodates All Head Shapes and Sizes Wide, 15 to 22,000 Hz frequency response Titanium-coated, high-polymer diaphragms deliver accurate sound Neodymium iron boron rare-earth-magnet structures for accurate sound reproduction Oxygen-free-copper voice coils for high signal clarity Closed leatherette ear cushions for maximum isolation and deep bass