Cando 30-1870G Green Inflatable Vestibular Disc, 13-51/64" Diameter, 300 lbs Weight Capacity Inflatable vestibular disc mimics both the movement and shape of the inflatable exercise ball when used on any seat It acts as a dynamic cushion to activate major muscle groups Use it on the floor as a standing disc for balance training, proprioception and strengthening of the lower extremities Each disc has one nubby side for a tactile feedback and stimulation and a flat side 300 lbs Weight capacity