Copper Moscow Mule Mug -COPPER 16 OZ. STAINLESS STEEL LINING - This is a more sanitary choice than the all copper competitors. Also, this will prevent that metal taste in your mouth after a sip. Double Wall Construction - keep your drink ice cold; ice will remain frozen for at least 2 hours! These are the highest quality stainless steel lined copper mugs available, the brass handles are firmly welded on and Stainless Steel Lasts Longer - 100% copper mug will rust over time through oxidation of the metal