PREMIUM MATERIAL - Interior is made from high-quality food-grade stainless steel SS304 which will never rust and is naturally BPA-free. Does not retain flavours or scents, so you can use it over & over again. The exterior and dividers are made from food-grade safe plastic. LEAK & SPILL PROOF - Between each stackable insulated compartment are heavy-duty silicone seals to lock in freshness, leaks, and odours. Each layer also has an individual lid which not only reinforces its leak-proof feature but also prevents messy food on the bottom of the above layer. MULTI-FUNCTIONAL – The exterior layer is microwavable. You can either use the exterior layer only which can be used in a microwave or use the stainless steel liner to hold the food, depend on your preference and the food you are going to take. SAFE MICROWAVE AND DISHWASHER USE - Feel free to use this box in the microwave. Removable compartment tray reheats food safely in the microwave and cleans up easily in the dishwasher. That’s why it is the best leak-proof bento box for kids. SAFE & HEALTHY - Interior is made from high-quality food-grade material, BPA-free, never rust, does not retain flavours or scents; The exterior and dividers are made from food-grade safe plastic, non-toxic and odourless; so you could use it with confidence.