Feature●Material: The surface is made of 304 stainless steel with a special liquid inside.●Advantages: physical cooling, longer, wireless cycle use, will not melt into water and affect the taste, avoid the harm to the human body caused by the use of ice cubes made from unclean water sources●Instructions: Clean it and put it in the refrigerator for about 2-3 hour before use, and then put it in a drink. Rinse after use and store in refrigerator.●Package Includes：4 x ice stones(18mm x 76mm) + cloth bag.If you want to faster, you can put more. It does not have a metallic taste, but pay attention to the weight that the cup can bear.●If you are not satisfied with our products, we are willing to reissue them for free or give them a full refund. Thank you for supporting us.Description Whiskey Stones 4PCS Bullet Shape 304 Stainless Steel Reusable Ice Cube Rapid and Chilling with Cloth Bag for drink(18mm x 76mm)