Stainless steel lunch box: The Warmeo Magic lunch box is made of high-quality stainless steel , which is durable, rust-free, and easy to clean, PUF insulation: The lunch box features PUF (Polyurethane Foam) insulation that helps keep food warm for longer periods of time, making it ideal for carrying hot meals to school, office during travel, Food grade BPA-free materials: The lunch box is made of food-grade materials that are BPA-free, ensuring that your food stays safe and healthy