VERSATILE SHAPE - Rectangular shape for easiness during storage/stacking, be it in cabinets, refrigerators, or freezers etc. STURDY CONSTRUCTION - Strong and solid PP (polypropylene) plastic material construction ensures long lives for the containers even when used in rough conditions. 100% AIRTIGHT, LEAK AND SPILL-PROOF - Specific design which helps in preserving and keeping the contents of the containers fresh. The lids feature silicone rubber which adds to the snap-on lock system that further assists in keeping the food fresh. MICROWAVE AND FREEZER SAFE - The plastic used is 100% BPA free. The containers (not the lids) are dishwasher, microwave, and freezer safe. They can be used in temperatures up to 80 degrees Celsius. 18 PIECE SET - Includes 9 containers with 9 lids of assorted sizes. 1 container with a capacity of 3,250ml, 2 containers with individual capacities of 2,350ml, 1 container with a capacity of 1,750ml, 2 containers with individual capacities of 1,250ml, 1 container with a capacity of 750ml and 2 containers with individual capacities of 550ml.