Thank you for viewing. Material: Natural stone, a cost-effective Four Seasons Garden. These are quite beautiful stones, and the minerals within are clearly visible, so I think you'll be very satisfied at this price. Size: Inner diameter approximately 17 cm As these are natural stones, there may be natural cracks and color variations. Also, they are strung with silicone rubber, so please be someone who can repair them yourself if they break. They are very fragile, so please refrain from dropping them or handling them roughly. Please also remove them during exercise. We can also repair them, but shipping and repair fees will apply. We will take a video during packaging, so we cannot accept claims for damage. Please be sure to take a video when opening the package. Due to the above reasons, we cannot accept returns or complaints. Thank you for your understanding.