1Build up your forearm strength and wrist strength, if insist to use, the effect of bodybuilding is remarkable. 2The arm power exerciser has a strong rebound, help you build the perfect body figure. 3Exercise shoulder, arm and back muscles to make the body healthy and strong. 4Non-slip rubber handle, conform to ergonomic designs, easy to grip and use. 5Made of carbon steel spring material, safe and eco-friendly, stable and durable.