I agree with Jeanne. Unfortunately, AcousticSheep has not got back to me after the initial response about the frequency of their headphones, when they provided incorrect information. They have taken the information on the frequency off their website and not replaced it yet. So I would be very weary to buy their product until they provide more technical information, if you are at more advanced levels of brain entrainment. I still like the format of their headphones though. I hope they will clarify matters about the frequency.
