The BeyerDynamic DT 770's are a set of high quality studio headphones. The studio that I work at has a pair of these on hand, although they aren't always used as headphones for monitoring during recording unless absolutely needed. The headphones have a closed back and reproduce a phenomenal range of frequencies from 5 Hz to 35 kHz. The DT 770's are also some of the most comfortable headphones that I've ever worn. They are really soft and fit nicely on your ears, while at the same time they cover up the sound so you won't be getting much bleed out of them. They are of course adjustable for different sizes and on the end of the cable is an 1/8" jack, although I believe when you buy a new pair of these you'll also get a 1/4" adapter. As far as sound quality is concerned, the BeyerDynamic DT 770's are hard to beat, as they are some of the fullest sounding headphones that I've used to date. They cover the full spectrum of frequencies incredibly well both on paper and in practice as you can really hear the difference here. While I'm weary of mixing on any headphones, if you were going to do it, these would be the pair to do so on. They have a great low end response to go along with a nice and crisp high end and a full bodied mid range. They're awesome for checking mixes on, but since they sound so good, their usefulness definitely extends beyond this. The price of the BeyerDynamic DT 770's may scare a few people away, but this is going to be the price you pay for a set of high end studio headphones like this, and sometimes even more. If you're looking for an all in one set of high end studio headphones, the BeyerDynamic DT 770's are a great way to go...