This product is made of high quality alloy, not easily deformed, comfortable feel. This product is the best product for you to exercise your wrist and arm, it builds-up your wrist and arm strength and helps improve power needed for Golf, Tennis, Bowling, Basketball, and other sports. 8mm thick sponge makes it more soft and comfortable. It has a attractive appearance and strong three-dimensional. It's very convenient to use and carry, can be used in any place.