Thank you for viewing. Material: Natural stone, Yozakura agate Size: Inner diameter 17 cm As it is a natural stone, there may be natural cracks and color unevenness. Also, as it is bound with silicone rubber, please be someone who can repair it yourself if it breaks. It is very fragile, so please refrain from dropping it or handling it roughly. Please also remove it during exercise. We can also repair it, but shipping and repair fees will apply. We will take a video during packing, 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, so please understand.