HSS Set Of 8 Reusable Stainless Steel Ice Cubes For Whiskey Wine Beverage With Tongs/Pincers;Non Toxic, Easy To Wash And Very Durable Material:Stainless Unlike ice cubes, they gently cool your drink without diluting them Size: approx. 20 mm x 20 mm x 20mm Freeze for 4-hour before using (suggested) Made from "soft" stone, these rocks won't scratch glassware