Premium Stainless Steel. Made of food-grade 18/8 stainless steel, durable and rust-Proof, easy to clean. Vacuum insulation: Double wall vacuum insulated, keeps hot up to 3 hours or cold up to 9 hours. BPA-free: BPA free lid with silicon rubber gasket, dishwasher safe, shatter-resistant. Convenient Handle: Full-loop handle comfortably fits into your hands, easy to grip and carry.