I've bought the Porta Pro Koss ca.2 months ago and am of sound begeistert.Zuerst the bad: The headphones do not work very stabil.Die connections are made of thin plastic and act therefore not very widerstandskräftig.Bisher but they have kept well , and the really good thing is not at all comes out particularly in the description, the way they ogether collapse, which saves a lot of space. The elegant appearance of the metal at the "ear trim" (Do not know what to call it otherwise) will unfortunately by the blue plastic behind gestört.Was is important for the real music fan, the sound, and is stunning, because it sounds absolutely clear. The bass is unbelievable what only from a size of these headphones possible ist.Mittlerweile I hear you using my headphones when on any speakers. If that style halfway like and who is looking for really good sound, for the Porta Pro a good Wahl.Ich would make him only FRIEND even if the processing is not very stable (!!) acts (!!). I had so far no Probeleme and forgive because of the sound, on the essentially matters 5 Stars. (Possibly it appears larger than it is in the picture!)