Ice Rocks Glasses Set GiftProduct Features: Material: Stone, Glass and Wooden box Can be used for any type of drinks The texture of the stone is natural, so the appearance may vary, color deep or shallow, have texture or not, but the function is the same. They are fast chilling, and reusable. Put the clean stones in the velvet bag to protect them. Suggested usage: Freeze the ice cube stone in the refrigerator for 3 hours, and place 3 of them in volume of 60 90ml of your drink.