Mainly made of premium food safe silicone which is durable enough for years. This collapsible silicone container is flexible, non-stick, and heat resistant. Leakproof-locking lids prevent wet food leaks. The collapsible design shrink down the size to half when the meal prep boxes are not in use. Perfect for storing and travel. When needed, just pop the containers out. These are great for meal prep, box lunch, food storage of both wet and dry foods, suitable for refrigerator, dishwasher etc. Best gift to your family and friends. Custom logo is available.