U.S. Jaclean Core Twist Balance Board -Engage your core muscles with this 10" mini twist disc with reflexology nodes. -A fun aerobic exercise that lets you twist your way to a tighter waist. -Regular use tones, improves balance and increases stability. Helps reduce the chances of injury or falls. -Increase energy, relieve stress and encourage weight loss. -Hold weights or a medicine ball for a more challenging workout.