The Ultra•Seal™ 3.1 Cup Rectangle food storage container features a green color-coded matching system to help find the correct lid and base combination without rummaging through the cupboards. The gasket and four latches in the lid create an airtight and watertight seal that keeps food fresh and prevents liquids from leaking. A vent in the lid releases steam when the container is placed in the microwave, and all containers store efficiently both when in use and when not in use. Ultra•Seal™ containers are freezer, microwave and dishwasher safe, as well as BPA-free and phthalate-free.