from a horse toy to a training aid, stacy's activity ball is a versatile tool for a wide range of riders. a dvd hosted by natural horsemanship expert stacy westfall shows you the many uses for this ball. it can be used as an aid in training horses, a tool to help you work on balance and improve seat position and a horse toy that offers hours of enjoyment. incorporating this activity ball into your training sessions helps desensitize your horse and reduce spooking or overreacting to new things. perfect for average-sized horses and riders. includes a pump for easy inflation. the ball's circumference should be approximately 93" when fully inflated with a height of 30". please inflate fully to help prevent horse from biting ball. supervision is recommended at all times. blue.