The Lock & Lock Classic range uses a patented 4 sided locking system, and a silicone seal, to create an air and water tight storage container for all of your needs. Ideal for everything from apple slices in your packed lunch to zips in your sewing kit. Suitable for both microwave and freezer, these containers are a great way to store, transport and heat food; they are also completely dishwasher safe and come with a lifetime guarantee.