I really like how this has several modes you can use, and I can feel my muscles tightening with this. I used this on my abs and thighs and the next day I was extremely sore. I felt like I had done a ton of sit ups and lunges. It is really easy to use, and not uncomfortable, but it can hurt/zap a little if you put the settings too high for what your body is comfortable with. I love that you can use this on several parts of your body.