High-quality 18/8 food-grade stainless steel Double-wall vacuum insulation: Keeps drinks cold for 24 hours and hot for 12 hours. Leak-proof and spill-proof design: Ideal for gym, school, or outdoor use. Durable and stylish with no retention of odors or flavors. Includes matching color chug or straw lid: Integrated handle for easy carrying, even when hands are sweaty.