Moscow Mule Copper Mug Set - 16 oz. (4-Pack) - Authentic Style Mule Mug - 100% Copper - No Filler Metals 4 - Pack Copper Mugs for Moscow Mules Classic Design for those who care about the finer things Conducts heat and cold with in seconds 100% Copper. No Stainless steel lining PureMule Copper Mugs are Straight Up Copper. No Filler, No Garbage, No Shinny Coating. You get what you want. A 16oz Mug Made of Pure Copper.