Selling over 10,000 Slam Ball per year, the Morgan slam balls are designed specifically for workouts that will require a ball to be dropped, thrown and/or slammed. Regular medicine balls are not designed to be used for these activities but it's all about the right tool for the job. Our Slam Balls are constructed with an ultra-durable, heavy-duty rubber shell and filled with fine black sand for fluid movement and instability. A rough textured surface allows for a high-quality grip even when wet. Each slam ball comes equipped with an air valve making it possible to adjust the air capacity and overall firmness, and also acts as a safety feature to assist in dampening the blow.