I have come to the conclusion that the Koss Sportapro is currently the best portable headphones in the world (and has been for at least the last 15 years as well). It's not just the ultra-clear complete immersion of a true sound experience, which would be more than enough, but the marvel of the ergonomic engineering as well. It fits as tight as a vise but feels so comfortable at the same time. I doubt if any headphone as good will be developed in the next 50 years. In fact it could be that it simply can not get any better. This is a headphone that deserves a lot more attention than it has received.