SPRI Medicine Ball – Thick Walled Heavy Duty Textured Surface Ball for Workouts, Endurance Training, Exercise – Easy to… $33.08 – $63.27 Make sure this fits by entering your model number. CLASSIC MED BALL: Body training tool that helps develop muscular strength, endurance, power, stability and joint integrity THICK WALLED: Thick walls increase durability and extend the life of the ball and the higher rubber content provides a better bounce – add air to increase the bounce and add variety to your workout