Jolly Mega Ball by Horsemen's Pride. This heavy duty inflatable ball is made specifically for horses. This durable exercise ball that can be used for enjoyment or training and is a favorite of Natural Horsemanship practitioners. Product Details: Inflatable Ball Foot pump is included Available Sizes: 25", 30" and 40" Be sure to choose the appropriate size ball that corresponds with the size of your horse. To ensure continued long lasting enjoyment, store your Jolly Mega Ball™ indoors when not under supervised use.