Jacky's Original Handmade Copper Moscow Mule Mug, Gift Set of 4 20 Oz Mugs, Free Recipe Book Included The mugs are made of sturdy a copper material, with a beautiful hammered design. Carefully polished to give it a wonderful shine. The mugs are highly durable and entirely handcrafted, suitable not only for Moscow mule, but also for beer and all other beverages. Special holiday mugs that comes in a gift set of four 20 ounce mugs. They have no nickel lining, ensuring high standard of originality and authenticity from a genuine seller. Features a smooth stainless steel interior which makes them easy to wash by hand.