Reusable ice cubes are generally available in three materials: 304/316 Food-Grade Stainless Steel, BPA-Free Plastic (PE/PP), and Natural Stone (Soapstone/Granite). Stainless steel offers the best thermal conductivity and a premium aesthetic, often filled with a non-toxic cooling gel (glycerol and water) to extend chilling time. Plastic versions are cost-effective and can be molded into various shapes and colors for branding, while Natural Stone provides a classic look for whiskey enthusiasts as they do not over-chill the drink.