Dolphy AB Wheel is best fitness device to get perfect abs sculpted in steel. An abdominal roller wheel is better than sit-ups or crunches training your core and obliques. Dolphy 4-wheels design, stable and better support. It is simple to use for all skills and fitness levels, from beginner to advanced pro. It's a sturdy abdominal roller wheel and not flimsy like most other abdominal roller wheels. The soft sponge grip longer than others, match the shoulder better, help poor posture.