The Polar Camel 20oz. Stainless Steel Polar Camel Travel Mugs feature double-wall, vacuum insulation. These travel mugs come with a slide lid to help prevent spills! They are 2X heat and cold resistant compared to other tumblers. Laser engraved leaving silver, stainless steel show-through imprint. This product is not recommended for dishwasher use. The perfect product to keep your drinks hot or cold while on the road.