With a product so inexpensive and effective if it feels forced to share our experience with! It's been a week and a half I worked with this tool and I must say I am extremely surprised, I had already read a lot of reviews praising the product and its effectiveness in a week but when we have results it is still fabulous enough surprising and motivating! The product is really cheap for an efficiency of thunder, however it is true that it takes a good abdominal basis, in any case, the first day it feels good abdominal pain level is the warm sense haha! But that's a good sign because its meaning it works well. We must practice the exercise, this may hurt a little back, especially at the beginning! I advise you to search for video of the year if you have any doubts. So I totally recommend this unit and thank you to Amazon for delivery quality we can never blame :)