The vibrating rod in the middle is made of fiberglass. After repeated tests, it is not easy to break for time and is beautiful and durable, Exercise more than 99% of the muscle fibers of the whole body, and drive the muscles to vibrate 300 times per minute. It widely applicable for fitness people, obese people, elderly people, relieve waist/back/shoulder pain and stimulate deep muscle vitality through high-frequency vibration.