Sportime Duck Walker Balance Boards (each measuring 23-1/4 x 5 x 3-1/2 inches) withstand 200 pounds each and allows children to rock from side-to-side, spin 360 degrees on a smooth surface, or walk like a duck. These are great aid for practicing balance control and coordination, as well as building and strengthening muscle. Boards are molded from reinforced polypropylene, offers both gross motor and vestibular exercises.