With the K 550s, AKG® engineers have struck a masterful balance between the noise-isolating qualities of closed-back headphones and the spacious, dimensional sound of an open-back design - creating reference-class headphones ideal for private listening both at home and on the go. 50mm drivers, the largest in the AKG product line, deliver great sound from your hi-fi system or virtually any portable device. The large ear cups and new headband design ensure an amazingly comfortable fit, and the 2D-axis mechanism folds flat to stow or go. Lightweight, comfortable and stylish: perfect at home and on-the-go Real Image Engineering for accurate definition and impression of width, distance and depth Closed-back design for a fully personal listening experience 50mm drivers for outstanding sound from any deviceLarger drivers, richer soundThe AKG® K550 reference-class headphones" 50-millimeter (2-inch) drivers are the largest of any AKG headphones in their product class. They deliver rich, lifelike sound across a frequency range of 12Hz to 28kHz, with the full dynamics and 3-D spatial imaging of a live performance. Their closed-back design ensures that you"ll hear your music exactly as its creators intended you to hear it, with little ambient sound to distract you. 2D-Axis folding mechanism for easy storage and portabilityUnlike most other full-size headphones, the AKG® K550 reference-class headphones fold flat - a convenient shape for fitting into a drawer at home or sa