bwgen u have to have headphones cuz its 2 frequencies, for example 400 hz and 404 hz. Each frequency will go through a different ear and it will kinda like lower your brain waves to 4hz. Its not really hypnoitization but its still pretty cool. You have to close your eyes and listen to it pretty loud for a few minutes. You might not think anythings going on but once you turn it off you zoom back into reality really fast which is fun.