Features: Material: Aluminum alloy Size: diameter 38mm Bearing type: Electroplated r188 bearing (r188 bearing is more durable) feature: It is a perfect size to carry and a wonderful toy for you to forget your fidget, anxiety and quit your bad habits wherever you are. Also it is a suitable desk toy for both adults and children. Is strong and durable. No matter how you treat it, even if you accidentally fall to the ground, it is still intact and not easy to break. Whether you are tired of work or study, just turn the ball easily, you can release the pressure of the day and let you have a rest. Our visual illusion is still a nice ornament. Putting it on your office desk or bedroom desk even shelves will definitely bring a different feeling. Generally it is also a good choice to send it to your friends as a gift.