The colorful light bar inside the ball changes color as the speed of the core increases, making exercise more engaging. Self-starting design eliminates the need for pull cords—simply follow the arrows and push to release the ball center to begin. The wrist ball is mechanically powered and requires no external power source. Centrifugal force generated by wrist motion and the internal rotating core allows continuous high-speed rotation. A secure wrist strap is included to help prevent accidental release during use. Designed to support hand, wrist, and forearm exercise, it may help relieve discomfort associated with repetitive strain and is suitable for strength training. This metal wrist exerciser features an automatic start mechanism activated by a simple push and release. Variable speed lighting enhances user experience and provides visual feedback based on rotational speed. Built with a durable zinc alloy core and a polycarbonate silicone shell, it offers reliable performance and resilience. Specifications: Core Material: Zinc alloy Shell Material: Polycarbonate silicone Color: Black Size: 70 x 70 x 55 mm Package Includes: 1 x Wrist exerciser with light