Hi im selling my used but basically brand new Monster Beat Studios, they have only been used about 3 times and packed back away in the box. When I went to use them last they would not turn on, I tried some different batterys but they didnt work (plus I dont even know if the batterys work). They still come wrapped as new, still have the original box and sleeve, the cables, jack adaptors, carry case and instructions. They cost £349.99 when I bought them, I have no idea what could be wrong with them and as I hardly used them I wont spend the time trying to repair them.