A copper mug is a drinking vessel made primarily from copper, known for its distinctive metallic appearance and excellent thermal conductivity. These mugs are often used to serve cocktails, particularly the popular Moscow Mule, which combines vodka, ginger beer, and lime juice. The copper material helps keep the drink cold, enhancing the overall experience. Copper mugs are typically lined with another metal, such as stainless steel or nickel, to prevent copper from reacting with acidic ingredients. They come in various sizes and designs, making them a stylish choice for both casual and formal occasions.