18-Piece glass food storage container set includes 9 glass containers and 9 matching locking lids in different sizes and shapes. The containers are designed to nest inside each other for compact storage, saving space. The locking lids are easy to close and provide an airtight seal. The glass containers are safe for use in the oven, microwave, freezer, and dishwasher, while the lids should be removed before heating. Both the containers and lids are BPA-free and made of high-borosilicate glass. If you are not satisfied with your purchase, please contact us for a replacement or with any suggestions for improvement. Your purchase is protected by our guarantee.