Automatic start design, need to push the core in the direction of the arrow, start by the internal spring, very easy and convenient.When it rotates, the cool colored lights inside will light up. It can kill time and add fun while restoring muscle soreness.Without any strange vibrations, it can rotate for a long time without worrying about it stopping when moving.The convenient design can be carried anywhere, whether in the office, gym or at home, it can be used as a toy to decompress at any time, and it can also exercise arm muscles.Wrist ball can promote blood circulation and increase the strength of fingers, wrists, hands, forearms, biceps, triceps and ligaments and shoulders, and restore muscle strength. Our products are made with the splendid quality materials and are designed to provide you with the best possible user experience.