Zak Designs Fluted Stainless Steel Double Wall Vacuum Tumbler with Insulated Button Lid Ruby, 12 oz, Multicolor 12 oz. Fluted Travel Tumbler has vacuum sealed double wall insulation which improves thermal efficiency; keeps beverage hot for 4 hours or cold for 11 hours. Insulated lid has one hand operation for easy drinking; the innovative liquid lock technology creates a leak-proof seal when lid is closed Tumbler fits under most single serve brewers and fits in most car cup holders; lid disassembles for easy cleaning; perfect for use at home or on-the-go BPA-free materials; stainless steel tumbler is durable and will not retain odor or flavor of beverages Dishwasher safe, but hand washing will extend life of tumbler and lid; do not microwave