Sit ups, crunches, leg raises, right and left elboy to knees, twists. And you can increase intensity on the control unit as your muscles get stronger over time.
The contour abs core sculpting system does 'work' in the sense that it will cause your abs to contract like you're doing crunches. But - its not good quality, I bought one and it broke after like 3...
Yes, they do work, and there are medical studies and journals to prove this.
However, they are not a miracle fat reducer, and to see the best results you will need to have a healthy diet and...