3 Removable Covers: : use the lids to stack the ice cube trays, keep the ice cubes clean and protect them from odors collected by the freezerClose the lid to prevent leakage (Note: the lid is not dishwasher and oven safe) ). Silicone material (food grade):: The ice cube trays are made of silicone and PP, are BPA free and certified by the LFGB. Easy release with a silicone base:: The unique design of the silicone base makes it easy to remove the ice cubes Rinse the bottom with water, press the bottom and the ice cube will come out quickly. Mini ice cube box:: each bowl contains a total of 6 large cubes ( 3 x 3 x 3 cm) of 18. Easy to clean and reusable:: they resist temperatures from -20 to 100 C and are safe to use in the refrigerator and microwave. Perfect for the freezer and for storing baby food.