I know the product by a friend, I tried a week before you buy: the mixture heat / pain is amazing 1éres the time and 1st minutes are painful (put a fine shirt in case) and the principle is to truly relax dessus.Cc'est against radical muscle tension (and in my case, I want to sleep after the session) and sessions on the stomach is effective against constipation. you can find out how to use Youtube or site MantraMat