LEAK-PROOF FOOD STORAGE: The SnapLock Collection by Progressive consists of stack-able, leak-proof containers that are great for home, office or on-the-go! GREAT FOR YOUR SANDWICH ON-THE-GO!: These containers are the perfect food container for storing and transporting your Sandwich SILICONE SEAL WITH LOCKING LID: It is designed with a silicone seal and locking clips creating a perfect leak-proof seal, making for safe storage and transportation on-the-go SPACE SAVING DESIGN: The unique design allows the containers to be stacked so the can save space in the pantry, refrigerator and freezer DISHWASHER SAFE AND BPA FREE: It is made from polypropylene and silicone and is BPA and Phthalate Free, Dishwasher Safe, Freezer Safe and Microwave Safe (clips must be unfastened before Microwaving).