The newly designed AKG K551 headphones are optimized for a fully immersive listening experience and for comfort. Starting with a 2-inch (50-millimeter) driver on each ear, these reference-class headsets use Real Image Engineering to create a highly realistic sound environment with a true sense of dimensional space. Lightweight, with a comfortable fit, AKG K551 headphones have incredible passive noise reduction and extremely low sound leakage levels that will keep you living blissfully inside your sound environment for hours on end.