While there are a number of options for cocktails, many of glass, copper truly is the cocktail-cup royalty when it comes to the mule. Not only is it perfectly suited to keep the temp of your chilly, bubbly Moscow Mule, but copper is a natural substance and is highly durable to everyday impacts and the inevitable effects of time. Ultimately, its conductivity makes it an ideal choice for cold beverages with complex combinations of flavors–like the Moscow Mule!