You'll be feeling the burn when you introduce a Cortex 4kg Medicine Ball into your workout. Adding a medicine ball into your routine is a great way to burn more calories and develop functional strength. A thick rubber casing makes our medicine balls exceptionally durable, allowing them to retain their shape over time. The rubber also creates a strong surface to grip during intense workouts. Feature Smaller in diameter compared to Wall Balls Come with a rubber shell for exceptional durability Equal distribution of weight across the ball for great consistency Warranty: 12 Months Parts replacement warranty