Material: High-quality SUS304 / SUS316 food-grade stainless steel interior and exterior.Insulation: Double-wall vacuum technology designed to keep meals hot or cold for up to 8 to 12 hours.Design Features: Diamond-textured anti-slip body, heavy-duty folding rubberized handle, secure screw lid, and a silicone leak-proof sealing ring with a built-in air release pressure valve.Interior: Typically includes 2 to 3 stackable inner stainless steel layers/compartments to store separate food items without mixing.