... workoutKey Specification-Materials: iron, PP, PVC,foam-easy to assamble-Designed for efficient sit-ups, abdominal work ... fitness level.3.Four or Six iron springs to support your body.4.When lying down,it will be ... back automatically.5.Use your strength of belly and waist to let it down,you will ... postion.9.Total core will help you to get fit with ease and happiness.Package:1.Includes DVD,Manual, ...