closed headset with dynamic bass for noise isolation HD 221 HD 221 Main Features Closed headset Neodymium magnets delivers bombastic bass-driven stereo sound Single-sided cable 1.On Ear Smartphone Headset HD 221 The closed, supra-aural acoustics screen out surrounding noise - the clatter of the train or the chatter of people sitting next to you - so you can immerse yourself in the excellent bass-driven Sennheiser stero sound. HD 221 headphones are fuly compatible with both portable devices as well as home stereo equipment, so you'll be able to enjoy amazing sound quality anywhere. 2. Dynamic speaker system with neodymium magnets The dynamic speaker system with neodymium magnets delivers bombastic bass-driven stero sound 3. Convenient Design Adjustable Head band Adjustable ear cups (up to 15°) Cushioned ear pads screen out surrounding noises Single-sided Cable HD 221 Composition HD 221 "Plug Adaptor(3.5 mm plug. 1.2m)" Safety Guide Enjoy music on the move HD 221 Specifications Impedance 16Ω Frequency Response 19 - 21,000 Hz Sound Pressure Level (SPL) 108 dB (1kHz/1Vrm) Jack Plug 3.5mm angled Cable length 1.2m