Stainless Steel Wine Tumbler Coffee Mug with Lid-12oz. The mug is insulated with vacuum double insulation. The double-layer insulation design ensures that your drink stays hot or cold for a long time. Let you enjoy your hot and cold drinks to your heart’s content. Drinking hole on top. The coffee mug is made of food-grade stainless steel, the inner liner will not produce any flavor and will not rust, hand washing is recommended. The main body of the coffee mug has a sturdy structure for long term use. Coffee mug handle is long and wide for finger grip.