These stackable, interlocking pots are perfect for space-saving and easy storage. They feature a totally airtight closure to keep food fresh, visible graduations in ml and oz for precise measurements, and a marking area for food identification using an erasable marker (not included). Made from durable polypropylene plastic, these containers are freezer and dishwasher safe. For reheating, simply place them in a bowl of warm water or steam them directly in the Babycook® bowl or any other steam pot warmer.