CanDo Firm Medicine Balls are ideal for exercise, workouts, warmups, core strengthening and stability training. Medicine balls improve muscle sensory balance (also known as proprioception), flexibility, help build resistance to injury and improve range-of-motion. Anyone involved in any level with body building, golf, baseball, basketball, football, tennis, soccer, hockey, swimming, MMA, boxing and just about any other athletic endeavor, will benefit from working with these balls. CanDo Firm Medicine Balls help build up critically vital core muscles, comprised of abs, obliques and the lower back. Please note, the Firm Medicine Balls contain Latex and may cause allergic reactions in some individuals. This is a set of 5 Medicine Balls including Yellow-2 lbs., Red-4 lbs., Green-7 lbs., Blue-11 lbs. and Black-15 lbs. Professionals recommend medicine ball training because of the variety of benefits it offers, especially to athletes of every level (pro, amateur and weekend). Medicine balls prepare the body for realistic motions. Many different rotational movements are possible with medicine balls that aren't possible with machines or other apparatus. An 8-15 lb. ball will give a good abdominal core workout. A 4-10 lb. ball is good for tossing exercises. A heavier ball in the range of 15-30 lbs. is ideal for leg exercises. 8 color-coded weights across four different sizes are available. Ranging from lightest and smallest to largest and heaviest: Yellow, Red, Green, Blue, Black, Silver, and Gold. CanDo Medicine Balls are non-slip and easy to clean. Suitable for home use but built tough enough for multi-user environments such as gyms and clinics.