The Pain Therapy System includes not only the benefits of TENS technology, but also Electrical Muscle Stimulation (EMS) and our proprietary Auto-Modulating pain relieving waves. It’s programmed to automatically change the stimulation at random to prevent the body from adapting. These 12 different wave forms simulate soothing and relaxing treatments. The most important difference about DR-HO'S® Pain Therapy System over the traditional TENS machine is that it is proven to provide pain relief in as little as 20 minutes of use.