The adhesive function allows you to connect the bottom of the unit to the lid. Stackable in different sizes. It does not add bulk to your storage shelf. Reusable, very durable. Clear so you can see the contents at a glance. Heat resistance: Main body: 202°F (100°C); Lid: 198°F (90°C); Cold resistance: -40°F (-40°C). Set products: 16.5 fl oz (473 ml) x 2 pieces