"The light-weight stereophones with modern design and excellent audio characteristics are ideal for all kinds of MP3 players - including your favorite iPod! Those who try Koss headphones for the first time are surprised just how close their sound is to what normally only comes out of much more expensive closed studio headphones - doubly so since the open design is generally regarded as inferior to closed headphones.
Features Dynamic element design for deep bass performance Comfort Zone setting on temporal pad for comfortable secure fit Multi-pivoting earplates and adjustable headband for added comfort Collapsible for maximum portability when listening on the go Includes convenient carrying case Includes 3.5 mm and 6.4 mm stereo plugs for home and portable use Straight dual entry 4 foot cord light-weight: 60 g 15-25000 Hz Distortion."
I can personally vouch for these headphones, in my opinion they are better than the Sennheiser range, almost indestructible, and look much cooler and i have owned both!
The first time i used them i was walking the dog. I heard church bells that i had never heard in that particular song before, and actually turned my head to look up behind me, expecting there to be a church there.
These cost two or three times more than this until recently, and come with Koss' limited lifetime warranty, where they repair or replace any fault for a flat fee of $6 to cover shipping (i think, please check somewhere first).
The only downside is that they leak sound quite badly, so if you intend to use these next to your parnter in bed you may end up on the couch. Also, don't [pick up the Sporta Pro model, the neckband version of the Porta Pro, as the sound is generally inferior.
Independent review and comparison with Sennheisers - http://www.goodcans.com/HeadphoneReviews/porta.htm