Primary Abdominal Exercise Wheel with Supporting Knee Pad Total Body Training You can easily adjust the weight by just changing how to hook the support tube, even beginner can start training without trying hard. You can increase the strength naturally with four level weight adjusting. Twin roller supports your body stable, you should not hurt your wrist or lower back from breaking posture. Your knees fit on the knee pads gently and well, your training posture also will stabilize. You can enjoy tube training to exercise bicep, shoulder and pectoralis major muscle. Total training of the whole body can be done as you like.