Improve Your Reaction Skill: While using this fight ball reflex punch exercise, your reaction skills will be enhanced. Besides, it improves your accuracy & eye & hand coordination & speed punching. Better for improve teenagers' coordination & reflex ability. Good for Your Health: You build muscles while increasing your stamina. Boxing this reflex ball is a good alternative for a gym. It will influence all muscle groups, really burn out your arms, chest, shoulders & upper back, perfect for calorie burning & conditioning Lightweight & Portable: Easy to carry & can be used in different occasions, you can take this boxing training ball with you anywhere, perfectly fit into your pocket or backpack. Question & Answer: Q: What is the diameter of the ball? Can I handle it by one hand? A: Size is similar to tennis; I can handle it by my h&. Q: How long is the elastic rope? A: It is very simple to cut, scissors can be done. The elastic rope total length is 2.0 meters (78 inches), & it can be cut to the length you need, also can be replaced when it lost its elasticity.