1. Material safety: Containers are made of 100% food-safe PP and silicone: non-toxic and odor-repellent, environmentally friendly, BPA-free. Super smooth surface on the inside to avoid grease and very easy to clean.2. Includes 4 containers: 13.2 * 3 * 9.8cm (350ml), 16.5 * 3 * 10.8cm (500ml), 18.5 * 12.2 * 3.2cm (800ml ), 21.8 * 13.8 * 3.2cm (1200 ml). 4 different sizes for a variety of different situations, picnics, travel, work, etc.3. Ingenious design: lid with 4-way click lock, leak-proof silicone sealing ring. Small valve on the top of each container for the release of water vapor. Allows for simple, compact storage, collapses to 1/3 of its original size for easy, saving you more than 60% space.4. Safe Use: For microwaves, dishwashers and refrigerators. Applicable temperature is -40 C ~ 120 C. Open the outlet valve if you are heating it in the microwave and using heating time no more than 5 minutes.5. Ideal Food Storage: Perfect for food storage. Easy to assemble and carry, it is the best lunch partner for children, but also ideal for adults to develop healthy eating habits and an ideal choice as a gift.