This set includes 18 glass food storage containers, featuring 9 rectangular jars with corresponding lids in sizes L (35.5 oz), M (21.6 oz), and S (12.5 oz; square jars in sizes L (27 oz), M (17.6 oz), and S (10.8 oz; round jars in sizes L (32 oz), M (22 oz), and S (13.5 oz), The design of these lunch boxes allows for nesting, enabling smaller containers to fit inside larger ones, saving space Simple Seal—Are you still worried about how to secure the lid? These 9 locking lids can be easily sealed without leaving your table or manual fixing; just use five fingers to lock them in place. This lid is highly compatible with borosilicate glass, making sealing not only simple but also more airtight This product is safe for use in ovens, microwaves, and dishwashers with a temperature range from -40°C/-40°F to 400°C/752°F.