Lock and Lock's patented four-hinge locking system with a silicone seal ensures the container is 100% liquid and airtight, keeping food fresher for longer. Having passed 3 million repetitive hinge working tests, the flexible and durable hinge remains tight after repeated use. Low permeability factor of containers ensures food stays fresher for longer than other brands. Impact, scratch, heat and stain resistant material ensures the containers are long-lasting and also ideal for transportation. Stackable, space-saving design is ideal for storing foods and keeping the kitchen cupboards and fridge neat and tidy.