Koss Pro4AAT Titanium Pro Headphones Titanium Coated High Polymer Titanium Diaphragm for Accurate Sound Reproduction Oxygen Free Copper Voice Coils for Signal Clarity Closed Ear Cushions for Maximum Bass and Isolation Stereophones, with 3.5mm plug, and 6.3mm adaptor Adjustable Slide Bars Ensure A Snug Fit Closed Pneumalite Cushions Form A Positive, Comfortable Seal Around The Ears Freq Resp: 10 Hz-25 Khz Imp: 250 Connectivity technology : Wired