They're a really cool portable, one of the best I've heard regardless of their age, a little aggressive sounding but terribly versatile to many genre's, and especially great at executing EDM and techno. they're basically a living legend and something not unlike ER4S everyone should try once. Usually when I get a piece of gear I sell in about a month and try something else, though every so often something comes along I simply must keep. HD251-ii is one of those headphones. They actually stay paired with my black 2nd edition Studio and the photo above is more for eye candy.
If you want something for on the go and just simply fun, keep your eye out for a pair Lee.
I had a pair and I liked them very much. Very fun headphones though not particularly detailed.