none, well they were light weight

WOOLY BASS! is all you hear, no mids no highs

Got these for iPod and other portable. Thought I was getting original Porta Pro. These were/are the Porta Pro2. Not sure if they are still made at this writing. At the time (2004) was all you could get, no Porta Pro sans 2 designation. These phones were terrible. All you could hear was wooly bass. Maybe they were deflective. I took them back to CC. God they were aweful. They original Porta Pro's shown as current models in production on Koss' website and Headroom.com are supposed to be much better but just read a review where the writer said they were bass heavy as well. Ugh!

Similar Products Used:

Sennheiser PX100 at near the same price and weight are 100X better sounding, 100X more neutral and ear friendly.