Stacy Westfall activity balls are a customer favorite! These versatile balls can be used as a training aid for horses, a tool to help a rider work on balance and seat position, or as a horse toy that offers hours of enjoyment. Help protect your activity ball from everyday wear and tear with our Activity Ball Covers. Small - Purple: Petite size makes it ideal for training smaller horses, as well as helping smaller riders work on their balance People will find it easy to handle, while horses will find its small size more of a challenge, making it perfect for mor advanced training exercises Perfect for use with shank bits Circumference should be approximately 68" when fully inflated Height: 20" Medium - Blue: Recommended for average-sized horses and riders Riders of average height will find this size perfect for working on their core muscles for improved balance and seat position Perfect for incorporating into training sessions to help desensitize horses and reduce spooking or overreacting to new things Circumference should be approximately 93" when fully inflated Height: 30" Large - Red: An ideal training tool for larger horses (as well as less advanced horses) as it is easier for them to control Not for use with shank bits because ball may bounce up and jar the shanks Circumference should be approximately 124" when fully inflated Height: 39" Pump included for easy inflation