Pros: Portable, works, and is actually usable
Cons: Feels cheap, EQ1 is unusable
I used this with my Beyerdynamic 860 and Ultimate Ears TripleFi 10. It works and does a great job for most music giving it a more full range of sound. I have tried it in my PC headphone out and mainly with my T989 Samsung Galaxy S2 as well as on an iPhone. Depending on the quality and type of music you will want to use EQ2, EQ3 or no EQ. EQ1 is a joke but the others have given much to the range of sound any device puts out not to mention it makes it significantly louder. For $25 I cannot complain, doesn't do as well as when I listen through my AVR525 but it is portable, cheap, and rechargeable.