Rage Fitness Slam Ball, Ideal for Cross Training, Core Exercises, Plyometric and Cardio Workouts Encased in an ultra-durable, heavy-duty rubber shell Rage Slam Ball is high endurance impact approved and performs in ways a medicine ball cannot. Textured surface allows for a high quality grip even when wet No bounce design proves to be ideal for various throwing and slamming routines. Equipped with an air valve making it possible to adjust the air capacity and overall firmness